BERKELEY 

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DEPARTMENT  OF  THE  INTERIOR. 

!.(>!.m;U'AL  AND  liKOGRAPHICAL  SURVEY  OF  THE  TKRIUTORlIih! 
<  i 

W.  POWELL,  OKI .1.1  MUST  IN  CJ 


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GEOLOGY 


'         OF   TI1K 


EASTERN  PORTION  OF  THE  UMA  MOUNTAINS 


A  REGION  OF  COUNTRY  ADJACENT  THERETO. 


WITH 


BY  J.  W.  POWELL.       ( 


WASHINGTON: 

GOVERNMENT     PRINTING      OFFICE. 
187C. 


K5M5 


^  -tx  JX  X 

JV^KSITV 

1  *    UF  | 

WIA.J 


G.VI  K     OF     I.ODORE. 


Y  OF 


PREFACE. 


The  region  of  country  embraced  in  the  map  which  accompanies  this 
report  is  one  of  great  geological  interest.  Three  great  categories  of  facts 
are  here  represented  on  a  grand  scale,  viz:  facts  relating  to  displacement, 
facts  relating  to  degradation,  and  facts  relating  to  sedimentation.  The  dis- 
placements arc  of  great  magnitude,  and  because  the  beds  involved  are  sedi- 
mentary strata  but  rarely  altered,  the  characteristics  of  these  displacements 
are  plainly  revealed,  so  that  in  our  studies  of  them  we  have  been  able  to 
arrive  at  conclusions,  both  quantitative  and  qualitative,  with  some  degree  of 
certainty. 

While  displacement  has  been  great,  degradation  has  also  been  great, 
yet  the  country  has  not  been  planed  down  to  a  general  base-level,  but  stands 
in  mountain  cliffs  and  escarped  hills,  where  the  strata  are  plainly  revealed.. 

The  formations  which  we  are  able  to  study  here  have  an  aggregate 
thickness  of  50,000  feet,  and  embrace  groups  of  Paleozoic,  Mesozoic,  and 
Cenozoic  Ages.  Throughout  nearly  the  entire  region  there  is  a  condition  of 
surface  which  renders  the  study  of  the  geology  comparatively  easy.  By 
reason  of  great  altitude  and  extreme  aridity  the  rocks  are  rarely  masked  by 
subaerial  gravels,  soil,  or  vegetation,  and  the  book  of  geology  lies  open. 
We  have  thus  been  able  to  collect  a  large  body  of  facts,  which,  in  the  fol- 
lowing volume,  have  been  arranged  in  such  order  as  it  seemed  would  best 
present  to  the  reader  the  general  geology  of  the  country.  Many  details 
have  been  omitted  which  would  have  been  given  had  the  facts  been  pre- 
sented as  they  w*ere  collected  in  the  form  of  an  itinerary,  but  it  was  though 
that,  such  a  method  would  result  in  encumbering  geological  literature  with 


a  mass  of  undigested  facts  of  little  value. 


Ill 


IV  PREFACE. 

It  may  be  well  to  indicate  here  the  general  routes  of  travel  by  which 
the  country  has  been  explored.  In  the  fall  of  1868  with  a  small  party  of 
men  I  crossed  from  the  White  River  to  the  Yampa,  and  camped  at  the  foot 
of  Junction  Mountain;  thence  I  passed  northward  across  the  Snake  River 
to  the  Pine  Bluffs,  and  thence  westward  across  Aspen  Mountain  to  the 
Green  River,  and  up  the  bank  of  that  stream  to  Green  River  Station; 
thence  I  crossed  to  Bryan,  on  Black's  Fork,  and  down  that  stream  to 
its  mouth,  then  went  south  to  the.  Cameo  Mountains;  thence  eastward 
to  Quien  Hornet  Mountain;  thence  to  Flaming  Gorge,  and  from  this 
latter  point  to  Ashley  Park,  and  from  Ashley  Park  to  Brown's  Park.  From 
Brown's  Park  I  went  through  the  Escalante  Peaks,  near  the  junction  of  the 
Yampa  with  the  Green ;  thence  eastward  past  Junction  Mountain  to  the 
White  River. 

The  course  thus  laid  down  is  the  general  one  of  the  pack  train,  but  I 
myself  branched  from  it  in  many  ways. 

On  this  journey  I  first  discovered  the  succession  of  Cenozoic  and  Meso- 
zoic  groups,  but  did  not  divide  the  Upper  from  the  Lower  Green  River,  nor 
did  I  draw  the  plane  of  separation  between  the  Upper  Green  River  and 
Bridger  Groups  where  I  do  now. 

Early  in  the  spring  of  18G9  I  again  crossed  from  the  White  River  to 
the  Yampa,  camped  at  the  foot  of  Junction  Mountain,  and  spent  a  few 
days  in  the  study  of  the  adjacent  region.  I  proceeded  thence  to  Brown's 
Park,  in  which  I  camped  for  a  few  days,  reviewing  the  geological  studies  of 
the  previous  fall.  I  then  passed  out  of  the  park  through  Red  Creek  Canon, 
from  its  head,  crossed  the  divide,  and  proceeded  westward  to  the  Green  River, 
and  camped  again  at  Flaming  Gorge  for  a  few  days.  Thence  I  went  up 
Henry's  Fork,  studying  the  region  on  my  way,  and  crossed  the  divide  to 
Fort  Bridger. 

A  few  weeks  Subsequent  1  started  on.  a  boat  trip  to  explore  the  lower 
Green  and  the  Colorado  River  of  the  West,  On  my  way  I  passed  through 
the  Uinta  Mountains,  stopping  from  time  to  time  to  make  sections  and  to 
make  geological  studies  of  the  country  along  the  walls  of  the  canons. 

Again,  in  1871,  I  had  a  boat  ride  down  the  river.  On  this  trip  Mr. 
.John  F.  Steward,  of  Piano,  Illinois,  was  my  assistant.  We  extended  our 
studies  on  either  side  of  1  lie  river  for  a  distance  of  from  ten  to  twentv  miles. 


PREFACE.  %  V 

In  1874,  I  started  with  a  pack  train  from  Green  River  Station,  went  up 
Little  Bitter  Creek,  across  Quien  Hornet  Mountain,  through  Red  Creek 
Canon  into  Brown's  Park;  thence  southeastward  to  the  junction  of  the  Snake 
River  with  the  Yarnpa,  where  it  was  crossed;  thence  across  the  Yampa 
Plateau  to  the  foot  of  Split  Mountain  Canon,  and  thence  to  the  Uinta  Val- 
ley. Returning  from  the  Uinta  Valley  I  visited  the  region  drained  by 
Ashley's  Fork  and  Brush  Creek,  crossed  the  Uinta  Mountains  to  the  head 
of  Sheep  Creek,  and  returned  to  Green  River  Station. 

The  course  thus  marked  down  was  that  followed  by  the  pack  train, 
which  moved  but  slowly,  usually  resting  two  days  out  of  three,  while  my 
own  line  of  travel  was  in  diverse  directions  from  this  general  route. 

In  1875,  I  again  started  with  a  pack  train  from  Green  River  Station, 
went  east  to  Rock  Springs  and  Salt  Wells,  thence  south  to  the  mouth  of  the 
Vermilion,  thence  to  the  eastern  foot-  of  the  Dry  Mountains,  thence  west 
through  Brown's  Park,  past  Flaming  Gorge  to  the  head  of  Sheep  Creek, 
and  thence  through  the  Cameo  Mountains  to  Green  River  Station.  On  this 
trip  also  the  train  moved  slowly,  and  my  studies  were  extended  many  miles 
in  either  direction  from  the  general  route. 

A  few  days  later  I  made  a  trip  to  Salt  "Wells  and  Bitter  Creek  Stations, 
and  particularly  examined  the  region  about  Black  Butte. 

The  last  part  of  the  descriptive  geology  has  been  greatly  condensed ; 
this  is  especially  the  case  with  the  description  of  the  structure  of  the  Yampa 
Plateau,  Junction  Mountain,  Diamond  Peak,  the  Dry  Mountains,  Brown's 
Park,  and  the  Aspen  Mountain  district.  It  was  intended  to  illustrate  the 
structural  characteristics  of  these  regions  with  a  series  of  diagrams  and  sec- 
tions, but  the  plan  was  abandoned  because  the  appropriation  was  exhausted. 
It  was  intended  also  to  prepare  a  chapter  on  the  physical  features  of  the 
region,  treating  of  the  mountains,  plateaus,  monoclinal  ridges,  hills,  parks, 
bad-lands,  and  alcove  lands,  and  further  treating  of  the  three  great  kinds  of 
drainage  found  in  the  region,  viz,  antecedent,  consequent,  and  superimposed; 
but  the  necessity  for  immediate  publication  Avas  so  great  that  this  plan  has 
also  been  abandoned,  and  to  this  subject  I  hope  to  recur  at  a  future  time. 

On  my  travels  during  the  year  1875,  Prof.  C.  A.  White  was  my  geo- 


VI  PKEFACE. 

logical  companion,  and  the  trip  was  made  largely  for  the  purpose  of  collect- 
ing fossils  at  localities  where  they  had  previously  been  discovered,  but 
to  which  sufficient  time  had  not  been  given  to  make  good  collections.  But 
many  places  of  interest  on  account  of  geological  structure  were  also  visited, 
and  I  had  the  good  fortune  to  have  with  me  an  experienced  geologist  on 
this  my  final  review  of  the  region ;  and  to  Professor  White,  whose  paper  on 
paleontology  appears  in  this  volume,  I  am  greatly  indebted.  Nor  must  I 
fail  to  mention  the  valuable  services  of  Mr.  Steward;  as  he  was  with  me  in 
one  of  the  earlier  years  of  the  work,  and  only  in  a  portion  of  the  region,  his 
studies  were  but  fragmentary,  and  the  results  have  not  been  directly  incor- 
porated in  my  general  account  of  the  geology  of  the  country.  I  feel  that  I 
have  not  done  him  full  justice  in  this  matter,  but  the  plan  of  publication 
would  not  permit  the  incorporation  of  his  notes  bodily;  nor  would  such  a 
course  have  done  him  justice,  from  the  fact  that  a  more  extended  study  lias 
greatly  modified  opinions  entertained  by  both  Mr.  Steward  and  myself  at 
that  time. 

For  the  map  I  am  indebted  primarily  to  the  labor  and  skill  of  Prof.  A. 
II.  Thompson,  who  has  been  my  collaborator  for  many  years,  but  in  the 
work  he  has  had  several  able  assistants;  and  in  the  year  1874,  Prof.  H.  C. 
De  Motte,  of  the  Illinois  Wesleyan  University,  traveled  with  me  for  the 
purpose  of  more  thoroughly  studying  the  details  of  Jhe  geography  more 
distant  from  the  river,  and  he  somewhat  extended  the  area  of  the  survey 
embraced  on  the  map. 

To  Mr.  Gilbert,  I  am  indebted  for  great  assistance  in  the  preparation  of 
the  graphic  representation  employed  in  illustrating  the  Report. 

The  diagram,  Plate  VII  of  the  atlas,  was  prepared  for  me  by  Mr. 
Archibald  R.  Marvine.  In  the  earlier  years  of  my  travels  in  the  Rocky 
Mountain  region,  I  studied  to  some  extent  the  Park  Mountains.  Subse- 
quently the  region  was  more  thoroughly  studied  by  parties  under  the 
direction  of  Dr.  Hayden,  and  in  his  connection  with  that  work  Mr.  Marvine 
traveled  over  much  of  the  same  ground  that  I  had  seen.  It  thus  happened 
that  we  frequently  discussed  together  the  country  which  had  been  visited 
by  both  of  us,  and  when  I  came  to  the  preparation  of  this  volume  Mr. 
Marvine  kindly  proposed  to  construct  this  illustration  for  my  use.  This  is 


PEEFACE.  VII 

perhaps  the  last  work  done  by  Mr.  Marvine ;  at  the  time  he  was  in  very 
ill  health,  and  a  few  days  after  sank  into  a  condition  from  which  he  never 
recovered,  and  we  now  have  to  mourn  the  loss  of  a  conscientious,  able,  and 
vigorous  geologist,  and  it  is  with  profound  sorrow  that  I  am  compelled  in 
acknowledging  his  courtesy  to  record  his  death. 

Mr.  J.  C.  Pilling,  for  the  past  three  years,  has  traveled  with  me  as 
stenographer  an 4  assistant  geologist,  and  to  him  I  am  indebted  for  the  col- 
lection of  a  great  body  of  details  of  diverse  character,  but  especially  in  the 
measurement  of  many  sections. 

Mr.  W.  Cleburn,  one  of  the  engineers  of  the  Union  Pacific  Railroad, 
and  who  has  been  engaged  in  that  work  for  many  years,  has  at  the  same 
time  interested  himself  in  the  geology  and  paleontology  of  the  region,  and 
to  him  I  am  indebted  for  many  favors,  and  especially  for  the  use  of  his 
valuable  collection  of  fossils. 

To  many  of  the  citizens  of  the  region  I  am  indebted  for  courtesy  and 
substantial  favors,  but  especially  to  Capt.  Pardon  Dodds,  of  the  Uinta  Val- 
ley, and  Mr.  S.  I.  Field,  of  Green  River  Station. 

J.  W.  P. 

The  following  note  from  Professor  White  is  inserted: 

DEAR  SIR  :  Since  my  report,  comprising  Chapter  III  of  this  volume, 
was  put  in  type,  further  investigation  of  the  fossils  collected  from  the  Canon 
of  Desolation  has  led  me  to  doubt  the  correctness  of  the  reference  I  have 
there  made  of  them  to  the  Point  of  Rocks  Group.  It  now  seems  probable 
that  they  properly  belong  to  the  Bitter  Creek  Group,  notwithstanding  the 
close  relationship  of  two  or  three  of  the  species  with  some  of  those  found  in 
strata  that  are  still  referred  without  doubt  to  the  Point  of  Rocks  Group. 

Further  collections  and  investigations  in  the  field  will,  however,  be 
necessary  before  this  question  can  be  definitely  settled. 
Very  truly  yours, 

G.  A.  WHITE. 

Prof.  J.  W.  POWELL. 


CONTENTS. 


CHAPTER  I. 

THREE   GEOLOGICAL  PROVINCES. 

Page. 

Geographic  characteristics  of  the  three  provinces  ...............................................  7 

General  characteristics  of  the  sedimentary  groups  ...................  ,  ..........................  8 

Characteristics  of  orogr  aphic  structure  .......................................................  9 

Types  of  orographic  structure  .............................................................  9 

Orographic  structure  of  the  Basin  Province  .....    .........................................  23 

Orographic  structure  of  the  Plateau  Province  ..............................................  25 

Orographic  structure  of  the  Park  Province  ................................................  26 

History  of  the  three  provinces  during  Ceuozoic  time  ........................................  32 

CHAPTER  II. 

SEDIMENTARY   GROUPS   OF  THE   PLATEAU   PROVINCE. 

Table  of  the  groups  of  sedimentary  strata  ......................................................  40 

Localities  where  the  several  groups  can  be  studied  .........................................  45 

Section  of  White  Cliff,  Vermilion  Cliff,  and  Shinarump  groups  ...........................  ...  53 

Uinta  Mountain  section  ...................................................................  57 

Cataract  Gallon  section  ...................................................................  58 

Grand  Cafion  section  .....................................................................  60 

Epochs  separating  the  groups  .............................................................  62 

Liguitic  coal  ..............  .........................  .  .....................................  73 

CHAPTER  III. 

INVERTEBRATE   PALEONTOLOGY   OF   THE   PLATEAU   PROVINCE. 

Letter  of  transmittal  ..................  "By  C.  A.  White,  M.  D."  ...................  J  ...........  ?4 


General  observations  .........................................................................  75 

Lower  Silurian  Age  .......................................................................  79 

Upper  Silurian  and  Devonian  Ages  ........................................................  79 

Carboniferous  Age  ........................................................................  79 

Mesozoic  Age  .............................................................................  80 

Cenozoic  Age  ...................................................................  .  .........  84 

Catalogue  of  fossils  ...............  .  ............  .  .....  .  .........  .  ............  ..  _____  .  ____  ......  88 

Carboniferous  Age  ........................................................................  88 

I 


2  CONTENTS. 

Tage. 
Catalogue  of  fossils — Continued.  . 

Mesozoic  Age  92 

Jurassic  Period 92 

Cretaceous  Period 94 

Cenozoic  Age 102 

Tertiary  Period 102 

Descriptions  of  new  species 107 

Carboniferous 107 

Jurassic 110 

Cretaceous 112 

Tertiary 125 

CHAPTER  IV. 

GEOGRAPHIC  DISTRIBUTION  OF  THE  GEOLOGICAL  FORMATIONS  IN  THE   UINTA  MOUNTAINS. 

Red  Creek  Quartzite 137 

Uinta  Group 141 

The  Carboniferous  groups 146 

The  Jura  Trias  groups 150 

The  Cretaceous  groups 153 

The  Cenozoic  groups 161 

CHAPTER  V. 

STRUCTURAL  GEOLOGY. 

The  eastern  portion  of  the  Uinta  Mountains 176\ 

Displacement 176 

Degradation 181 

Disintegration 182 

Transportation 184 

Scholium  relating  to  the  epoch  of  upheaval  of  the  Basin  Ranges 198 

Sedimentation 198 

The  Yampa  Plateau 202 

Scholium  relating  to  the  terms  "  upheaval,"  "  subsidence,"  &c 203 

Junction  Mountain 204 

Diamond  Peak 204 

The  Dry  Mountains 206 

Brown's  Park 208 

Aspen  Mountain  district 209 


CHAPTER    I. 


THREE  GEOLOGICAL  PROVINCES. 

The  Colorado  Elver  of  the  West  drains  a  vast  system  of  plateaus.  On 
'these  plateaus  are  lone  mountains,  short  ranges  and  groups  of  volcanic  cones, 
and  the  principal  affluents  of  the  river  have  their  sources  in  high  mountains 
that  stand  on  the  rim  of  the  great  drainage  basin.  There  is  no  considerable 
valley  along  the  course  of  the  Colorado  River  north  of  the  thirty-fifth  par- 
allel nor  along  the  course  of  any  of  its  principal  tributaries.  The  streams 
run  chiefly  in  deep  canons  which,  with  other  important  topographic  features, 
serve  to  divide  the  area  into  plateaus.  The  district  of  country  of  which  I 
thus  speak  is,  in  its  important  characteristics,  a  plateau  region. 

This  plateau  character  was  well  recognized  by  Dr.  Newberry.  In  his 
report  to  Lieutenant  Ives,  page  41,  he  says:  "The  Colorado  rises  in  a  thou- 
sand sources  at  an  elevation  of  from  ten  to  twelve  thousand  feet  above  the 
sea,  on  the  western  side  of  the  Rocky  Mountains.  Descending  from  their 
fountain  heads,  its  tributaries  fall  upon  a  high  plateau  of  sedimentary  rocks 
which  forms  the  western  base  of  these  mountains  and  occupies  all  the  inter- 
val between  them  and  the  great  bend  of  the  Colorado  River  where  the  river 
enters  the  volcanic  district  already  described;"  and  elsewhere  in  that  vol- 
ume he  makes  frequent  mention  of  these  characteristics. 

Mr.  Blake,  in  the  third  volume  of  the  Pacific  Railroad  Surveys,  Part  4, 
page  42,  also  mentions  this  topographic  character  as  follows : 

"Extent  of  the  table  lands  ivest  of  the  Sierra  Madre. — This  is  a  convenient 
point  from  which  to  take  a  general  view  of  the  broad  expanse  of  the  great 
plain  that  lies  between  the  Sierra  Madre  and  the  mountains  which  form  the 


4  THREE  GEOLOGICAL   PROVINCES. 

eastern  rim  of  the  Great  Basin.  From  the  Sierra  Madre  up  to  this  place 
the  survey  followed  the  eroded  valleys  of  the  streams,  and  the  vision  WMS 
bounded  on  both  sides  by  their  high  and  rocky  banks,  composed  not  only 
of  the  edges  of  thick  horizontal  strata,  but  often  capped  with  the  harder  and 
more  unyielding  solid  lava.  The  observer  as  he  passes  westward  from  the 
mountains  is  thus  placed  below  the  general  level  of  the  plateau,  which  does 
not  become  apparent  to  him  unless  he  stands  upon  the  top  of  the  mesas  find 
can  thus  cast  the  eye  over  the  whole.  The  point  already  reached  in  the 
description  is  about  half  way  between  the  Sierra  Madre  and  the  high  mount- 
ains of  San  Francisco,  and  here,  as  we  have  seen,  the  upper  strata  of  the 
plain  are  denuded  and  washed  away,  so  that  the  banks  of  the  streams  are 
not  so  high,  and  the  country  appears  more  level  or  gently  rolling.  From 
this  place  the  vision  is  unbounded  toward  the  north,  except  by  the  horizon. 
The  plain  stretches  far  away,  without  any  vestige  of  a  mountain  range. 
Indeed,  it  is  the  continuation  of  this  plateau  which  rises  upon  the  flanks  of 
the  Park  and  Wasatch  Mountains  at  the  far  north,  and  through  which  the 
waters  of  Grand  and  Green  Rivers  cut  their  deep  canoned  channels.  Farther 
south,  these  streams  unite  to  form  the  great  Colorado,  which  is  also  found 
traversing  this  grand,  plateau." 

Our  studies  of  this  great  plateau  region  have  not  progressed  so  far  that 
we  are  able  to  clearly  define  its  boundaries,  but  these  studies  have  shown 
that  the  region  is  complex  topographically  as  well  as  geologically  and  is  in 
fact  composed  of  many  tables; 

In  this  region  the  succession  of  sedimentary  strata  is  unlike  any  series 
which  has  been  studied  elsewhere  in  North  America ;  different  groups  and 
different  groupings  of  fossils  are  found;  a  different  series  of  unconformities 
is  observed  and  the  displacements  by  faulting  and  folding  have  characteris- 
tics not  commonly  observed  elsewhere.  All  these  facts  seem  to  warrant  the 
conclusion  that  this  plateau  region  should  be  considered  as  a  distinct  geologi- 
cal province,  and  in  this  brief  report  and  others  which  are  to  follow  I  shall 
so  consider  it. 

A  notice  of  its  geographic  connection  with  the  surrounding  country  is 
needed.  That  portion  of  the  United  States  west  of  the  one  hundredth  merid- 
ian lies  at  a  great  altitude  above  the  sea.  The  exceptions  to  this,  as  immedi- 


THE   ROCKY  MOUNTAIN   REGION.  5 

ately  along  the  Pacific  coast  and  the  narrow  vallevs  of  some  of  the  princi- 
pal streams,  are  but  trivial.  The  rivers  descend  so  rapidly  from  the  upper 
regions  that  few  of  them  are  of  value  as  highways  of  commerce;  the  valleys 
proper  are  narrow:  treeless  plains,  cold,  arid  table  lands,  and  desolate 
mountains  are  the  principal  topographic  features.  The  more  conspicuous 
of  these  are  the  mountains;  lone  mountains,  single  ranges  and  great  groups 
of  ranges  or  systems  of  mountains  prevail.  Owing  to  great  and  widely 
spread  aridity,  the  mountains  are  scantily  clothed  with  vegetation,  and  the 
indurated  lithologic  formations  are  rarely  masked  with  soils,  and  the  rocks, 
as  they  are  popularly  called,  are  everywhere  exposed;  hence  all  these  mount- 
ains are  popularly  known  as  the  Rocky  Mountains.  But  there  is  more 
than  one  system  of  mountains,  and  later  writers  wishing  to  be  more  definite 
speak  of  the  Cascade  Mountains,  the  Coast  ranges,  the  Sierra  Nevada,  the 
Wasatdi  Mountains,  &c.  But  in  an  important  sense  the  region  is  a  unit; 
it  is  the  generally  elevated  region  of  the  United  States;  it  is  the  principal 
region  of  the  precious  metals ;  it  is  the  region  without  important  navigable 
streams:  it  is  the  arid  land  of  our  country  where  irrigation  is  necessary  to 
successful  agriculture.  But  above  all  it  is  the  rocky  region;  rocks  are 
strewn  along  the  valleys,  over  the  plains  and  plateaus ;  the  canon  walls 
are  of  naked  rock;  long  escarpments  or  cliffs  of  rock  stand  athwart  the 
country,  and  everywhere  are  mountains  of  rock.  It  is  the  Rocky  Mountain 
region.  There  is  a  necessity  for  popular  purposes  for  some  general  name 
and  this  one  so  appropriate  will  doubtless  continue  to  be  used,  and  it  would 
seem  best  not  to  attempt  to  confine  its  application  to  any  more  restricted 
area  ;  but  as  our  geographic  and  geological  knowledge  increases  so  that  we 
are  able  to  reasonably  and  appropriately  define  distinct  ranges  and  systems 
of  mountains  within  this  great  group,  other  distinctive  names  should  be  given 
t<»  such  ranges  and  grouj 

Influenced  by  this  consideration,  in  speaking  of  the  mountains  that  stand 
about  the  Plateau  Province  I  shall  use  names  for  certain  systems  which 
seem  appropriate  to  characterize  them  as  distinct  from  other  systems  within 
the  #reat  Rocky  Mountain  region. 

The  eastern  affluents  of  the  Colorado  River  have  their  sources  in  the 
lofty  mountains  that  stand  as  walls  ab«»ut  the  crreat  parks  of  Southern  \Vy«i- 


6  THREE   GEOLOGICAL  PROVINCES. 

ming,  Colorado,  and  Northern  New  Mexico,  and  these  mountains  constitute 
a  system  as  well  denned  as  we  may  hope  for  geographic  systems  to  be  de- 
fined by  nature;  and  since  my  studies  in  that  region  in  1867— '68,  I  have 
been  accustomed  to  speak  of  them  as  the  Park  Mountains.  The  system  is 
composed  of  many  ranges,  some  wrell  defined,  others  complex^inclosing,  or 
nearly  so,  the  North,  Middle,  South,  and  San  Luis  Parks,  with  many  minor 
valleys  and  parks;  and  there  are  short  outlying  spurs  and  ranges  with  other 
parks  and  valleys.  The  principal  mountain  ranges  are  composed  of  nieta- 
morphic  rocks  with  unaltered  sedimentary  beds  on  their  flanks.  Some  of 
the  more  western  mountains  are  chiefly  of  this  latter  material,  and  many 
of  the  subsidiary  mountains  are  of  eruptive  origin.  Altogether  they  con- 
stitute a  geological  province  characterized  by  a  great  development  of  meta- 
morphic  crystalline  schists  with  patches  and  structural  basins  of  marine  and 
lacustrine  sediments,  and  a  complicated  series  of  vulcanic  formations. 

Southward  •  from  the  Oregon  line,  through  Western  Utah,  Nevada, 
Southeastern  California,  and  perhaps  across  the  Colorado  River  in  Western 
Arizona,  many  short  and  more  or  less  distinct  north  and  south  ranges  are 
found.  The  valleys  and  plains  separating  these  ranges  are  covered  with 
rather  late  subaerial  gravels  masking  the  underlying  formations.  The 
ranges  are  composed  of  metamorphic  crystalline  schists  with  Paleozoic  beds 
on  their  flanks,  or  sometimes,  even  in  large  part  of  Paleozoic  materials  both 
complicated  to  a  greater  or  less  extent  with  eruptive  beds;  these  eruptive 
beds  themselves  sometimes  forming  the  principal  component  parts  of  the 
ranges. 

The  little  streams  that  have  their  simrces  in  these  mountains  empty 
into  salt  lakes,  or  elsewhere  their  waters  are  lost  in  the  sands;  as  it  is  popu- 
larly said  they  disappear  in  sinks.  The  most  important  of  these  is  the 
Great  Salt  Lake,  but  there  are  many  other  basins  without  drainage  to  the 
sea.  A  few  of  the  ranges  are  drained  into  the  Colorado  River.  To  this 
group  Mr.  G.  K.  Gilbert  has  given  the  name  Basin  Range  System,  which 
seems  appropriate. 

It  will  be  found  convenient  also  to  treat  the  area  occupied  by  this  group 
as  a  distinct  geological  province.  It  has  a  series  of  sedimentary  beds  differ- 
ing widely  from  the  Plateau  Province;  they  are  older,  and  the  sediments  of 


GEOGEAPHIC   CHARACTERISTICS   OF  THE   THREE   PROVINCES.      7 

the  latter  were  in  large  part  derived  from  the  former.  The  Basin  Province 
was  the  dry  land  that  fed  the  sea  and  great  lakes  of  the  Plateau  Province 
through  a  long  period,  while  many  groups,  each  thousands  of  feet  in  thick- 
ness, were  deposited. 

Thus,  for  convenience  of  geological  discussion,  I  speak  of  three  great 
geological  provinces — the  Park  Province,  the  Plateau  Province,  and  the 
Basin  Province — in  order  from  east  to  west. 

The  area  included  in  these  three  provinces  lies  east  of  the  Sierra  Ne- 
vada and  west  of  the  Great  Plains.  In  a  general  way  the  northern  boundary 
is  marked  by  the  North  Platte,  with  its  proper  upper  continuation  the  Sweet- 
water  River  whose  minute  upper  ramifications  interlock  with  those  of  the 
Shoshoni  River,  which  latter  is  a  continuation  of  the  northern  boundary 
until  it  is  crossed  by  the  forty-third  parallel  of  north  latitude.  When  the 
region  along  the  middle  course  of  the  Shoshoni  River  is  more  thoroughly 
studied,  the  Basin  Range  System  may  be  carried  much  farther  north  than 
we  are  warranted  in  doing  with  our  present  knowledge;  but  I  am  inclined 
to  the  opinion,  from  the  fragments  of  geological  description  which  we  have 
from  that  country,  that  another  distinctly  marked  group  will  eventually  be 
recognized  here,  having  for  one  of  its  characteristics  a  great  development 
of  eruptive  rocks.  The  southern  boundary  of  the  three  provinces  I  am  not 
able  to  clearly  define. 

It  may  be  well  to  state  somewhat  more  categorically  the  characteristics, 
geographic  and  geological,  on  which  I  propose  to  divide  this  great  area  into 
three  provinces. 

GEOGRAPHIC  CHARACTERISTICS  OF  THE  THREE  PROVINCES. 

The  Basin  Ranges  are  short,  more  or  less  distinct  north  and  south 
ridges  separated  by  desert  valleys  which  reveal  broad  stretches  of  sub- 
aerial  gravels  concealing  the  underlying  formations.  The  general  drainage 
is  to  interior  salt  lakes  and  sinks,  but  in  the  northeast  corner  there  is  a 
limited  district  drained  by  some  small  tributaries  of  the  Shoshoni,  and  in 
the  southeast  there  is  a  small  district  drained  by  the  Rio  Virgen  into  the 
Colorado  River  of  the  West. 


8  THUEE   GEOLOGICAL   PROVINCES. 

The  Plateau  Province  is  composed  of  many  tables  bounded  by  canon 
and  cliff  escarpments.  On  these  tables  stand  lone  mountains,  irregular 
groups  of  mountains,  and  short  ranges.  It  is  drained  by  the  Colorado 
River  of  the  West  and  its  tributaries. 

The  Park  Province  is  characterized  by  broad,  massive  ranges,  sometimes 
distinct,  sometimes  coalescing  so  as  to  include  the  great  parks.  The  lofty  peaks 
that  serrate  these  ranges  stand  over  snow  banks  that  are  perennial  reservoirs 
for  a  multitude  of  streams  whose  waters  on  one  hanc).  are  gathered  into  the 
Colorado  River  of  the  West,  and  finally  discharged  into  the  Gulf  of  Cali- 
fornia ;  and  on  the  other  hand  they  are  gathered  into  the  Mississippi  and 
the  Rio  Grande  del  Norte  to  be  discharged  into  the  Gulf  of  Mexico. 

Thus,  in  the  three  provinces,  we  have,  first,  desert  valleys  between 
naked  ridges ;  second,  high  plateaus  severed  by  profound  gorges ;  and, 
third,  massive,  high  mountains  with  shining  snow  fields. 

GENERAL  CHARACTERISTICS  OF  THE  SEDIMENTARY  GROUPS 

OF  THREE  PROVINCES. 

The  Basin  ranges  are  composed  of  Paleozoic  rocks  with  Eozoic  schists 
below,  and  in  the  Humboldt  Mountain  district  some  Mesozoic  and  Cenozoic 
rocks  are  found.  In  the  Plateau  Province,  Cenozoic  and  Mesozoic  rocks 
prevail,  though  some  of  the  important  plateaus  are  of  Carboniferous  beds ; 
and  in  a  few  places  deep  corrasion  has  revealed  still  older  Paleozoic  and 
even  Eozoic  formations.  The  Park  Mountains  are  chiefly  Eozoic  Since 
that  age  the  region  has  been  intermittently  under  the  dominion  of  the 
waters,  and  Paleozoic,  Mesozoic,  and  Cenozoic  rocks  are  found  at  horizons 
interrupted  ]>y  gaps  in  the  general  series  that  are  represented  by  dry  land 
periods,  wl.:le  the  last  orographic  agencies  have  left  but  fragments  of  these 
antecedent  formations. 


TYPES   OF   OROGRAPHIC   STRUCTUKE.  9 

CHARACTERISTICS  OF  THE  OROGRAPHIC  STRUCTURE  OF  THE 

THREE  PROVINCES. 

TYPES  OF  GEOGRAPHIC  STRUCTURE. 

It  seems  convenient  to  give  a  general  account  of  the  types  of  oro- 
graphic  structure  in  the  region  under  consideration  before  characterizing 
each  province  by  its  special  type. 

In  this  discussion  I  wish  to  use  certain  terms  with  a  restricted  or  rela- 
tive meaning ;  i.  e.,  in  treating  of  anticlinal  and  synclinal  flexures  I  shall 
speak  of  those  portions  of  the  sedimentary  beds  which  are  adjacent  to  the 
anticlinal  axes  as  having  been  upheaved,  and  those  portions  near  their 
synclinal  axes  as  having  subsided.  Again,  "in  blocks  which  are  bounded  by 
faults  and  tilted,  I  shall  speak  of  such  portions  as  are  at  a  higher  level  as 
having  been  uplifted,  and  portions  occupying  a  lower  level  as  thrown.  In 
such  cases  I  do  not  wish  to  commit  myself  to  any  theory  of  upheaval  or 
collapse  in  the  change  of  the  relation  of  the  several  parts  of  these  beds  to 
the  center  of  the  earth. 

In  treating  of  the  structure  of  the  mountains  under  consideration  it  is 
necessary  to  distinguish  two  great  classes,  viz,  those  composed  of  sedimen- 
tary strata,  'altered  or  unaltered,  and  those  composed  of  extravasated 
material. 

MOUNTAINS  COMPOSED  OF  SEDIMENTARY  STRATA. 

I.— APPALACHIAN   STRUCTURE. 

The  structure  of  the  Appalachian  Mountains,  with  closely  appressed 
folds  and  axial  planes  tipped  back  from  the  sea,  the  modifications  of  these 
folds  by  faults,  and  the  primary  and  concomjtant  forms  of  tile  mountains, 
have  been  clearly  explained  by  the  Messrs.  Rogers  and  later  writers,  and 
have  formed  the  basis  of  many  discussions  concerning  geological  dynamics. 
This  Appalachian  structure  needs  no  further  mention  here,  as  it  is  a  type  of 
structure  which  so  far  has  not  been  found  in  the  region  described  above,  and 
should  it  be  found  hereafter  it  will  simply  be  an  exceptional  type  to  those 
known  to  prevail. 


10 


THREE   GEOLOGICAL   PROVINCES. 


II.— SIMPLE  ANTICLINAL  STRUCTURE. 

Mountains  or  short  ranges  carved  from  simple  anticlinals  are  sometimes 
found,  though  this  type  of  structure  is  not  a  prevailing  one.  Usually  in 
such  a  case  the  great  mountain  mass  lies  in  the  central  zone  of  the  uplift. 
The  fold  is,  of  course,  always  found  truncated  by  erosion,  and  the  moun- 
tains represent  but  the  difference  between  the  amount  of  upheaval  and  the 
amount  of  such  erosion.  When  not  complicated  by  other  types  of  structure 
the  strata  dip  on  all  sides  from  the  center  of  upheaval,  gently  or  more 
abruptly,  but  the  sides  of  the  folds  are  never  closely  appressed.  Such 
mountains  in  primary  form  are  gently  rounded  in  general  outline,  modified 
by  the  erosion  of  the  streams  running  down  their  sides.  Sometimes  such 


FIG.  1. — Section  through  Junction  Mountain,  north  and  south. 


FIG.  2. — Section  through  Junction  Mountain,  east  and  west. 

B.  P.,  Brown's  Park  ;  8.  C.,  Sulphur  Creek ;  J.  T.,  Jura  Trias;  U.  A.,  Upper  Aubrey  ;  L.  A.,  Lower 

Aubrey ;  R.  W.,  Red  Wall ;  U.,  Uinta. 

• 

mountains  are  severed  by  rivers  running  longitudinally,  transversely  or 
obliquely  through  them ;  the  rivers  themselves  having  their  sources  in 
regions  far  away  and  passing  through  the  mountains  in  their  courses  to  the 
sea.  In  Northeastern  Colorado  a  short  distance  above  the  junction  of  the 
Snake  River  with  the  Yampa,  stands  Junction  Mountain,  which  serves  as  a 


UINTA   STRUCTURE.  11 

fine  illustration  of  this  type  of  structure.  The  mountain  is  divided  into  two 
unequal  parts  by  a  canon,  through  which  the  Yampa  River  runs.  The 
axis  of  the  mountain  has  a  north  and  south  direction. 

Figure  1  is  a  section  through  this  mountain,  in  a  north  and  south  direc- 
tion, along  the  axis  of  upheaval.  Figure  2  is  a  section  through  it  in  a 

transverse  direction. 

i 

CONCOMITANT    FORMS. 

1.  Monoclinal  Ridfjes  on  the  Flanks. — Under  conditions  which  are  so  well 
known  as  to  need  no  further  explanation  here,  monoclinal  ridges  or  hog- 
backs  are  formed  on  the  flanks  of  such  upheavals,  and  sometimes  such 
monoclinal  ridges  are  of  such  magnitude  as  to  be  dignified  with  the  name  of 
mountains.     Where  two  or  more  series  of  indurated,  inclined  beds  are  sep- 
arated by  extensive  series  of  softer  material,  two  or  more  monoclinal  ridges 
may  be  formed. 

2.  Monoclinal  Ridges  only. — Sometimes  we  find  that  an  anticlinal  up- 
heaval has  been  eroded  in  intaglio,  so  that  there  is  no  great  central  moun- 
tain mass,  but  the  axis  of  upheaval  is  the  site  of  a  valley  or  low  plain,  but 
the  monoclinal  ridges  on  the  flanks  remain. 

3.  Inclined  Plateaus. — Where  the  anticlinal  upheaval  has  a  great  ampli- 
tude, as  compared  with  the  vertical  uplift,  the  beds  incline  but  slightly. 
Under  such  conditions  inclined  plateaus   or  mesas   are  found  instead  of 
monoclinal  ridges,  usually  having  steep  escarpments  facing  the  axis  of  the 
flexure. 

III.— UINTA  STRUCTURE. 

In  the  Uinta  Mountains  we  have  a  great  range  carved  from  an  anticlinal 
upheaval,  the  axis  of  which  has  an  easterly  and  westerly  trend,  and  is  more 
than  one  hundred  and  fifty  miles  in  length.  It  terminates  abruptly  against 
the  Wasatch  Mountains  on  the  west  and  is  cut  off  by  the  short,  abrupt  anti- 
clinal of  Junction  Mountain  on  the  east,  the  latter  having  its  axis  in  a  north 
and  sQuth  direction.  There  are  several  important  facts  observed  in  the 
study  of  this  great  flexure.  Its  axis  has  been  lifted  above  the  level  of  the 
sea  about  thirty  thousand  feet,  and  above  the  level  of  the  adjacent  country 


12  THREE  GEOLOGICAL  PROVINCES. 

about  twenty-five  thousand  feet.  From  flank  to  flank  the  flexure  is  about 
fifty  miles,  but  varies  much  in  width.  We  find  on  either  flank,  many  miles 
from  the  axis,  a  line  of  maximum  flexure,  which  line  presents  a  subparallel- 
ism  with  the  meandering  axis.  These  lines  have  the  effect  of  two  mono- 
clinal  flexures  in  opposite  directions,  separated  by  the  broad  table,  diversified 
"by  elevated  valleys  and  peaks  of  which  the  great  mass  of  the  Uinta  Moun- 
tains is  composed.  But  the  portion  between  these  monoclinal  flexures  or 
lines  of  greatest  flexure  is  itself  gently  flexed.  In  many  places  that  which 
I  have  called  the  line  of  greatest  flexure  is  indeed  a  fault,  in  one  place 
on  the  north  side  of  the  Uinta  Mountains  having  a  throw  of  twenty  thousand 
feet.  On  the  south  side  the  line  of  greatest  flexure  is  very  irregular,  being- 
complicated  in  some  places  by  faults  having  uplifts  opposed  to  the  down- 
throw of  the  flexure.  On  either  side  the  great  displacement  is  partly  by 
faulting,  partly  by  flexing,  and  either  flank  is  a  zone  of  diverse  displace- 
ment where  the  strata  are  faulted,  flexed,  twisted  and  contorted  in  many 
ways. 

The  character  of  these  displacements  in  the  Uinta  Mountains  is  illus- 
trated in  Plates  1,  2,  and  3  of  the  Atlas,  and  in  a  subsequent  chapter  the 
subject  will  be  more  fully  discussed. 

The  simplest  topographic  forms  produced  by  such  displacements  under 
conditions  of  erosion  in  general  outline,  are  plateaus  with  gently  rounded 
summits  and  abrupt  shoulders  on  the  flanks;  but  such  general  outline  is 
often  modified  by  the  corrasion  due  to  antecedent  or  superimposed  drain- 
age; that  is,  by  the  corrasion  of  streams  that  head  in  remote  regions  and 
pass  through  these  uplifts  either  longitudinally,  transversely  or  obliquely, 
as  in  the  case  of  Simple  Anticlinals.* 

There  are  other  modifications  which  sometimes  greatly  obscure  the 
general  topographic  outline  due  to  consequent  drainage,  i.  e.,  the  local 
drainage  which  is  due  to  the  upheaval  itself  and  which  produces  inter- 
esting 

CONCOMITANT    FOEMS. 

1.  Subsidiary  Plateaus. — Sometimes  the  streams  which  head  near  the 
axis  of  such  an  upheaval,  as  they  meander  to  the  flanks,  excavate  valleys 

*  For  an  explanation  of  what  is  meant  by  antecedent  and  superimposed  drainage,  the  reader  is 
referred  to  the  Report  on  the  Exploration  of  the  Colorado  River  and  its  Tributaries,  page  160,  ct  scq. 


UINTA  STRUCTURE— CONCOMITANT  FORMS.  13 

and  divide  the  great  block,  which  is  a  plateau  in  general  outline,  into 
minor  plateaus  which  are  separated  by  intervening  but  elevated  valleys. 
This  is  especially  the  case  where-  the  streams  in  their  upper  courses 
follow  for  some  distance  the  strike  of  the  beds  before  turning  to  cross 
the  more  or  less  abrupt  lines  of  maximum  flexure.  Sometimes  these 
streams  run  in  deep  gorges;  in  such  cases  the  plateaus  are  bounded  by 
canons. 

2.  Projecting  Ridges. — When  these  consequent  streams  starting  near 
the   axis  of  upheaval  take   a  somewhat  direct  course   across  the   strike, 
the  general  plateau  is  cut  into  a  series  of  sharp,  abrupt  ridges  having  a 
trend  at  light  angles  to  the  strike  or  general  axis  of  upheaval.     Thus  the 
points  of  the  ridges  face  the  plain  below  and  are  separated  by  deep  gulches 
and  canons,  and  the  observer  on  the  plain  below  sees  before  him  what 
appears  to  be  a  line  of  peaks  separated  by  intervening  gulches  and  valleys, 
and  is  apt  to  misunderstand  the  topographic  character  of  the  great  mass 
which  is  before  him. 

3.  Axial  Peaks. — At  some  stages  in  the  progress  of  erosion  the  channels 
of  consequent  drainage  inosculate,  and  about  their  heads  gorges  are  formed, 
with  towering  amphitheaters.      In  such  cases  an    irregular  line  of  crags 
and  peaks  will  be  found  along  the  axis  of  upheaval.     These  I  call  axial 
peaks. 

4.  Flanking  Peaks. — Sometimes  we  find  a  very  hard  bed  or  group  of 
beds  underlaid  by  more  friable  strata  on  a  flank  of  the  upheaval,  which 
harder  beds  have  been  carried  away  by  erosion  from  those  portions  of  the 
upheaved  mass  nearer  the  axis.     In  such  cases  each  projecting  ridge  is 
crowned  with  a  true  peak.     I  call  these  flanking  peaks. 

5.  Interrupted  Monoclinal  Piidges. — On  the  flanks   of  these  upheavals, 
but  farther  from  the  axis  than  the  flanking  peaks,  monoclinal  ridges  are 
often  found  sometimes  broken  by  gaps  which  are  the  channels  of  inter- 
mittent or  permanent  streams,  and  these  ridges  are  very  irregular    and 
often  interrupted.     Where  the  downthrow  is  by  simple  flexure,  a  complete 
series  is  formed.     Where  it  is  partly  by  flexing  and  partly  by  faulting, 
some  of  the  monoclinal  ridges  disappear.     Where  the  faulting  is  on  the 
side  of  the  zone  of  maximum  flexure  nearest  to  the  axis,  the  ridges  of  the 


14  THREE  GEOLOGICAL  PROVINCES. 

upper  beds  appear ;  but  where  the  faulting  is  on  the  side  of  the  zone  of 
maximum  flexure  farthest  from  the  axis,  the  ridges  of  the  lower  beds  appear; 
and  where  the  displacement  is  chiefly  or  entirely  by  faulting,  there  are  no 

monoclinal  ridges. 

IV.— KAIBAB  STRUCTURE. 

In  the  region  under  discussion  we  often  find  the  sedimentary  beds 
broken  into  great  blocks  by  faults  or  their  homologues,  monoclinal  flexures, 
and  these  blocks  have  been  gently  tilted  in  broad  masses.  I  have  dis- 
cussed this  subject  somewhat  at  length  in  my  Report  on  the  Exploration  of 
the  Colorado  River  of  the  West  and  its  Tributaries,  published  in  1875  ;  and 
in  Figure  3  I  reproduce  a  section  and  bird's  eye  view  of  the  plateaus  north 
of  the  Grand  Canon,  which  was  used  in  that  volume.  An  examination  of 
this  will  fully  reveal  the  characteristics  of  what  I  have  called  the  Kaibab 
structure.  The  grand  topographic  features  which  result  from  this  structure 
are  plateaus  with  broken  edges  where  they  are  bounded  by  faults,  flexed 
edges  where  they  are  bounded  by  monoclinal  flexures,  and  with  escarp- 
ments where  they  are  bounded  by  canons  or  lines  of  cliffs. 

CONCOMITANT    FORMS. 

1.  Cliffs  of  Displacement. — When  a  plateau  is  bounded  on  one  side  by 
a  fault,  the  edge  of  the  plateau  is  an  escarpment  often  so  abrupt  as  to 
present  a  more  or  less  irregular  line  of  cliffs. 

2.  Slopes  of  Displacement. — When  the  displacement  is  a  flexure  rather 
than  a  fold,  the  edge  of  the  plateau  is  a  broken  slope.     I  have  discussed 
these  cliffs  and  slopes  of  displacement  somewhat  at  length  in  the  volume 
already  quoted  several  times,  page  182  et  seq. 

3.  Monoclinal  Ridges  on  the  Flanks. — On  the  flanks  of  these  monoclinal 
flexures,   under   proper   conditions  which    have    already  been    described, 
monoclinal  ridges  are  formed. 

4.  Monoclinal  Ridges  with  Plateau  Carried  Aivay. — As  in  simple  anticlinal 
upheavals  the  central  mass    may  be  entirely  carried  away  leaving  but 
monoclinal  ridges,  in  like  manner  in  the   Kaibab  structure  the  principal 
plateau  mass  may  be    carried  away  leaving  only  the  monoclinal  ridges. 
This  I  have  also  discussed  in  the  volume  already  quoted. 


Paria  Platean 


Virgin  Valley 


Pine  Valley  Mountain 


"(        > '   V  ,/  V 

I     ,;'   • 


Paria  Fold. 
Echo  Cliffs. 


Marble  Cation. 

East  Kaibal)  Fold. 

Kaibab  Plateau. 
West  Kaibab  Fold. 

Kanab  Plateau. 
Kauab  Cafion. 

Eauab  Plateau. 

To-ro'-weap  Fault. 
U-in-ka-ret  Mountains. 

Hurricane  Fault. 
Shi'-wits  Plateau. 


Grand  Wash  Fault. 
Grand  Wash. 


I 

•a 


a  a> 
TS 

SH 


KAIBAB  STRUCTURE—  CONCOMITANT  FORMS.  15 

5.  Projecting  Jtidf/cs. — It  is  seldom,  perhaps  never  the  case  that  the 
strata  of  one  of  these  plateaus  are  left  by  the  general  displacement  in  a  hori- 
zontal position  ;  but  every  block  is  tilted  more  or  less,  and  often  a  valley 
appears  at  the  foot  of  the  slope,  and  the  streams  which  head  on  the  opposite 
brink  of  the  plateau  have  excavated  valleys,  leaving  intervening    ridges 
which  project  into  the  valley,  having  an  effect  somewhat  like  that  described 
as  one  of  the  concomitant  forms  of  the  Uinta  structure.  On  •  2» 

6.  Cliffs  of  Erosion. — An  inclined  plateau  may  be  bounded  on  the 
upheaved  side  by  an  escarpment  of  erosion,  and  such  an  escarpment  is 
gradually  carried  back  by  an  undermining  process  from  the  line  of  greatest 
upheaval.     The  drainage  of  such  a  plateau  is  usually  from  the  brink  of 
this   escarpment  toward  the  valley  on  the  opposite   side  ;    yet  a  minor 
drainage  is  found  which  carves  out  deep  gulches,  and  the  cliffs  of  erosion 
have  deep  reentrant  and  sharp  salient  angles. 

7.  Buttes. — Sometimes  the  gulches  which   form   the    deep,   reentrant 
angles  of  a  line  of  cliffs  have  lateral  gulches,  which  by  continued  erosion 
coalesce,  and  the  salient  angles  are  gradually  cut  off  from  the  escarpment, 
which  is  ever  retreating.     In  this  manner  buttes  are  formed  as  outliers  of 
cliffs. 

8.  Cameo  Mountains. — Wherever  considerable  areas  of  horizontal  or 
nearly  horizontal  strata  are  found  sufficiently  elevated  above  the  base  level 
of  erosion,  and  such  areas  are  drained  by  two  or  more  subparallel  water 
courses,  the  lateral  drainage  of  these  water  courses  will  gradually  inosculate 
in  their  upper  ramifications,  and,  carving  out  deep  channels,  will  leave 
behind  mountains  of  horizontal  strata.     Such  mountains  are  often  of  great 
beauty.     This  is  especially  the  case  where  the  beds  are  of  different  texture 
and  color,  when  the  mountains  will  be  terraced  and  buttressed  in  beautiful 
regularity,  and  banded  with  the  colors  which  are  characteristic  of  the  several 
beds  of  which  they  are  composed. 

A  few  miles  north  of  the  Uinta  Mountains,  on  the  west  side  of  the 
Green  River,  a  group  of  such  mountains  are  found,  to  which  I  have  given 
the  name  Cameo  Mountains,  and  I  call  this  the  Cameo  structure. 


16  THREE  GEOLOGICAL  PROVINCES. 

V.— BASIN  RANGE  STRUCTURE. 

When  the  blocks  into  which  a  district  of  country  Jias  been  broken  by 
faults  are  greatly  tilted  so  that  the  strata  dip  at  high  angles,  the  uplifted 
edges  of  such  blocks  often  form  long  mountain  ridges.  Such  ridges  have 
the  general  appearance  of  the  monoclinal  ridges  already  described  as  con- 
comitants of  other  types  of  structure  ;  but  in  this  case  the  ridges  constitute 
the  chief  mountain  masses  themselves,  and  form  another  general  structural 
type.  The  monoclinal  ridges  are  due  to  the  erosion  of  upheaved  strata ; 
these  ridges  are  due  to  displacement ;  they  may  also  be  eroded,  but  in  so 
far  as  erosion  has  progressed  the  ridge  like  structure  is  obscured.  Many  of 
the  rido-e  like  mountains  of  the  Basin  Province  have  this  structure.  Such  a 

O 

ridge  is  composed  of  monoclinal  strata,  the  one  side  presenting  a  bold  escarped 
front,  the  other  a  more  gently  sloped  back  conforming  to  a  greater  or  less 
degree  with  the  dip.  Sometimes  the  ridges  themselves  are  faulted  longitud- 
inally, transversely  or  obliquely,  and  the  faults  may  be  slight  or  of  great 
magnitude ;  but  the  more  common  structure  is  a  simple  ridge  with  slight 
transverse  or  oblique  faults. 

CONCOMITANT    FOEMS. 

1.  Monoclinal  Ridges  on  the  Sack. — On  the  backs  of  these  Basin  ranges 
monoclinal  ridges  have  been  observed. 

VI.— ZONES  OF  DIVERSE  DISPLACEMENT. 

In  this  region  many  zones  or  irregular  areas  of  country  are  found  to 
be  divided  into  small  blocks  by  faults  and  flexures  running  in  diverse  direc- 
tions, and  these  may  be  horizontal  or  be  tipped  at  high  or  low  angles,  or 
even  be  overturned.  The  total  effect  of  this  diverse  displacement  may  be 
to  uplift  the  area  above  or  depress  it  below  the  adjacent  country  or  not  to 
change  its  relative  altitude.  These  features  are  exhibited  on  a  small  scale 
within  a  limited  area,  usually  so  elongated  as  to  be  termed  a  zone. 

During  the  past  season  Mr.  Gr.  K.  Gilbert  has  studied  an  area  where  this 
diverse  displacement  is  by  faulting,  and  the  faults  are  of  no  great  magnitude, 
and  the  blocks  into  which  the  area  has  been  severed  are  either  not  tilted  or 
but  slightly  so.  This  presents  the  simplest  illustration  of  this  type  that  has 


FIG.  4. — Bird's-eye  view  of  a  portion  of  the  Musinia  Zone  of  Diverse  Diaplaeeinent.  The  area  represented  is  six 
miles  square.  The  base  line  shows  the  sea-level.  The  tract  is  drained  by  Saliiia  Creek,  which  unites  its  branches 
in  the  center  and  flows  through  the  canon  on  the  left. 


JT 


FIG.  5.— Deduced  from  Fig.  4.    A  restoration  of  the  displaced  rocks  as  they  would  appear  had  there  been  displace- 
ment but  no  degradation. 


ZONES  OF  DIVERSE  DISPLACEMENT. 


17 


yet  been  discovered.  It  is  simply  the  Kaibab  structure  on  a  very  small 
scale.  Fig.  4  is  a  bird's  eye  view  of  the  blocks  mentioned.  In  the  section, 
in  the  foreground,  the  heavy  line  represents  the  summit  of  the  highest  Cre- 
taceous group.  Fig.  5  is  a  diagram  of  the  same  region  showing  the  blocks 
into  which  it  is  severed,  and  the  same  restored  to  the  condition  they  would 
have,  had  there  been  no  denudation. 

On  the  south  side  of  the  Uinta  Mountains,  and  east  of  the  Green  River, 
another  comparatively  simple  area  has  been  studied  by  myself.  This  zone 
of  diverse  displacement  is  on  the  flank  of  the  great  Uinta  upheaval.  These 
displacements  are  chiefly  by  flexures  rather  than  by  faults,  and  the  blocks 
arc  more  tilted  and  'contorted  than  in  the  last. 

In  Atlas,  Plate  No.  4,  we  have  a  stereogram  representing  these  displace- 
ments, and  in  a  subsequent  chapter  the  subject  will  be  more  fully  discussed. 


A. — Simple  Anticlinal  displacement. 


B.— Uinta  displacement. 


C. -—Kaibab  displacement. 


D. — Basin  Range  displacement. 


E. — Zone  of  Diverse  displacement. 
*  FIG.  U. — Types  of  Displacement. 

Many  other  areas  for  more  complex  than  these  have  been  discovered 
where  a  zone  has  been  broken  into  blocks,  and  these  blocks  tipped  and 
contorted  in  diverse  ways  and  directions  like  the  blocks  of  ice  crowded  in 
an  oddy  of  a  northern  river  at  the  time  of  its  spring  flood.  The  topographic 
features  found  in  such  areas  are  zones  of  irregular  hills.  Fio-ure  6  is  a 

r>  00 

2  P  G 


18  THREE  GEOLOGICAL  PROVINCES. 

diagram  illustrating  the  general  types  of  displacement  heretofore  discussed. 
A  represents  a  Simple  Anticlinal  displacement ;  13  a  Uinta  displacement ; 
C  a  Kaibab  displacement ;  D  a  Basin  Range  displacement ;  and  E  a  Zone 
of  Diverse  displacement, 

MOUNTAINS  COMPOSED  IN  WHOLE  OR  IN  PART  OF  EXTRA- 

VASATED  MATERIAL. 

We  are  not  able  in  the  present  state  of  our  knowledge  to  draw  legiti- 
mate conclusions  concerning  the  relation  of  the  eruptive  rocks  so  widely 
distributed  through  all  three  of  these  geological  provinces,  but  the  following 
types  of  structure  have  been  observed. 

VII.— TABLE  MOUNTAIN  STRUCTURE. 

We  often  find  beds  of  sedimentary  strata  preserved  from  erosion  by  a 
capping  of  lava.  Such  are  usually  called  table  mountains;  the  underlying 
strata  may  be  horizontal  or  inclined.  Earlier  stages  of  this  structure  are 
seen  in  mesas  or  low  tables,  and  sometimes  in  valleys  or  gulches  which 
have  been  filled  with  extravasated  material,  and  erosion  has  proceeded  to  a 
limited  extent  on  either  side  of  these  harder  masses  carrying  away  the 
softer  sedimentary  material  and  leaving  the  harder  volcanic  rocks  in  the 
midst  of  the  valley,  and  this  may  have  an  elevation  lesser  or  greater  than 
that  of  the  adjacent  country  beyond  the  rim  of  the  valley. 

A  fine  example  of  a  table  mountain  is  found  in  Pilot  Butte,  in  Wyo- 
ming Territory. 

VIII.— UINKARET  STRUCTURE. 

Simple  sheets  of  lava  may  be  poured  into  a  valley  or  on  a  plain,  and 
serve  as  a  protection  to  the  sedimentary  beds  which  are  immediately  under- 
lying them  and,  as  the  erosion  of  the  adjacent  country  not  thus  protected 
progresses,  new  vents  may  be  formed  along  the  edges  of  such  sheets  and 
at  a  lower  level.  Still  erosion  progresses,  and  still  new  floods  of  lava  are 
poured  out,  and  still  at  lower  levels,  until  a  mountain  is  left  behind  with  its 
central  mass  composed  of  sedimentary  material,  but  covered  on  the  summit 


TU-SEIAR  STRUCTURE—  VOLCANIC  STRUCTURE.  19 

and  flanks  with  irregular  and  overlapping  patches  of  lava.  Thus  lava  bed 
is  imbricated  on  lava  bed,  but  unlike  the  tiles  of  a  roof,  the  upper  edge  of 
the  lower  sheet  is  placed  on  the  lower  edge  of  the  upper.  This  struc- 
ture is  well  represented  in  the  Uinkaret  Mountains  in  Northern  Arizona,  and 
has  been  more  fully  discus/sed  by  me  elsewhere,  vide  The  Exploration  of 
the  Colorado  River,  &c.,  page  1 99  et  seq. 

IX.— TU-SHAR  STRUCTURE. 

When  a  plain  or  valley  which  receives  extravisated  material  from  below 
remains  at  a  base  level  of  erosion  during  the  period  of  successive  eruptions, 
flood  of  lava  is  piled  on  flood  of  lava  until  a  vast  mass  of  material  is  accu- 
mulated from  which  the  rains  and  streams  carve  mountains.  The  several 
beds  of  which  such  a  mountain  mass  is  composed  are  exceedingly  irregular, 
from  three  causes:  first,  each  bed  as  poured  out  was  an  irregular  mass, 
due  to  its  degree  of  fluidity  arid  the  character  of  the  ground  on  which  it 
was  poured;  second,  each  bed  was  more  or  less  modified  by  erosion,  which 
occurred  after  it  was  poured  out,  and  before  it  was  covered  by  a  subsequent 
flood;  and,  third,  the  general  mass  has  been  eroded  to  a  greater  or  less  ex- 
tent in  producing  the  present  forms. 

The  volcanic  activity  being  in  a  region  where  movements  of  displace- 
ment are  in  progress,  it  is  often  the  case  that  the  structure  of  this  class-  of 
mountains  is  greatly  modified  by  such  displacements.  Mountains  composed 
of  such  irregular  beds  of  lava  are  of  frequent  occurrence  in  the  region 
under  discussion.  A  fine  example  is  seen  in  the  vicinity  of  the  town  of 
Beaver,  Utah  Territory,  in  what  are  known  as  the  Tu-shar  Mountains. 

X.— VOLCANIC  STRUCTURE. 

When  many  eruptions  come  successively  from  the  same  vent,  and  each 
is  a  comparatively  small  amount,  cones  are  built.  Cones  of  such  simple 
structure  are  of  frequent  occurrence  in  the  region  under  discussion.  Great 
complex  cones  such  as  are  found  in  other  parts  of  the  world  do  not  occur, 
but  a  few  double  and  one  triple  cone  has  been  observed.  The  great  majority 
of  the  cones  observed  are  built  of  cinders  on  broad  sheets  of  lava,  and  are  in 
fact  concomitant  forms  of  lava  mesas.  Such  cones  are  comparatively  ephem- 
eral, as  the  scoria  and  ashes  of  which  they  are  composed  yield  readily  to  atmos- 


20  THREE  GEOLOGICAL  PROVINCES. 

pheric  degradation.  Where  such  a  cone  exists,  still  having  a  well  defined 
crater,  its  condition  testifies  to  the  lateness  of  its  origin,  and  all  the  facts 
relating  to  the  sheet  of  .lava  on  which  it  rests  fully  corroborate  the  conclu- 
sion. From  such  evidence  we  are  able  to  infer  the  recency  of  ,much  of  the 
volcanic  activity  in  the  three  provinces.  If  the  human  history  of  America 
could  be  carried  back  to  as  early  a  date  as  it  has  been  in  Asia,  it  cannot  be 
doubted  that  the  earlier  chapters  of  that  history  would  be  replete  with  the 
accounts  of  volcanic  fires. 

XL— HENRY  MOUNTAIN  STRUCTURE. 

Sometimes  we  find  the  sedimentary  strata  displaced  by  a  quaquiversal 
upheaval  and  the  same  fractured,  and  through  these  fractures  floods  of  lava 
have  poured,  and  these  may  lie  in  patches  about  the  flanks  of  the  mount- 
ains, or  stand  in  dikes  where  the  walls  of  the  crevice  have  been  swept  away 
by  denudation.  In  the  Henry  Mountains  we  have  a  fine  illustration  of  this 
type  of  structure.  These  mountains  have  been  studied  by  Mr.  Gilbert 
during  the  past  season,  and  in  his  preliminary  report  he  says  :  "  The  erup- 
tions of  the  Henry  Mountains  are  of  a  character  entirely  novel  to  me,  and 
they  were  studied  with  an  interest  stimulated  by  surprise.  A  description  of 
a  single  one,  though  it  will  not  stand  for  all,  will  serve  to.  illustrate  the  type. 
.  Mount  Ellsworth  is  round,  and  its  base  is  six  or  eight  miles  broad.  The 
strata  of  the  plain  about  it  tire  horizontal  on  every  side.  Near  the 
mountain  the  level  strata  become  slightly  inclined,  rising  from  all  sides 
toward  the  mountain.  At  its  base  the  dip  steadily  increases  until  on  the 
steep  flanks  it  reaches  a  maximum  of  forty-five  degrees.  Then  it  begins  to 
diminish,  and  the  strata  arch  over  the  crest  in  a  complete  dome.  But  the 
top  of  the  dome  has  cracked  open,  and  tapering  fissures  have  run  out 
to  the  flanks,  and  they  have  been  filled  with  molten  rock,  which  has  con- 
gealed and  formed  dikes.  Moreover,  the  curving  strata  of  sandstone  and 
shale  have  in  places  cleaved  apart  and  admitted  sheets  of  lava-  between 
them.  So  the  mountain  is  a  dome  or  bubble  of  sedimentary  rocks  witli  an 
eruptive  core,  with  a  system  of  radial  dikes,  and  with  a  system  of  dikes  in- 
terleaved with  the  strata.  It  is  a  mountain  of  uplifted  strata,  distended  Jind 
permeated  by  eruptive  rock." 


TYPES  OF  MOUNTAIN  STRUCTURE.  21 

In  the  foregoing  characterization  of  certain  types  of  structure  found  in 
these  regions,  I  have  not  attempted  to  adopt  a  system  of  exact  classifica- 
tion, which  should  be  both  inclusive  and  exclusive  as  the  types  do  not 
admit  of  such  classification.  No  "  hard  and  fast  lines  "  can  be  drawn.  I 
have  simply  attempted  to  indicate  the  important  types  with  their  primary 
and  concomitant  forms. 

It  is  manifest  that  the  structure  of  a  sedimentary  mountain  will  depend 
primarily  upon  two  elements — the  type  of  the  displacement  and  the  char- 
acter and  extent  of  erosion.  The  erosion  may  be  antecedent  or  superim- 
posed, or  it  may  be  consequent,  or  these  methods  may  be  combined,  and 
the  erosion  may  be  modified  by  dip,  texture,  and  other  characteristics  of 
the  beds  producing  concomitant  forms. 

For  convenience,  I  subjoin  the  following : 

SYNOPSIS  OF   THE   TYPES   OF   MOUNTAIN  STRUCTURE 
RECOGNIZED  IN  THE  FOREGOING  DISCUSSION. 

MOUNTAINS     COMPOSED    OF    SEDIMENTARY    STRATA,    AL- 
TERED OR  UNALTERED. 

I.— APPALACHIAN  STRUCTURE. 

(Not  found  in  the  three  provinces.) 

II.— SIMPLE  ANTICLINAL  STRUCTURE. 

Primary  topographic  form.     Plateau  with  rounded  vertical  outline. 
Concomitant  forms  :   1.  Monoclinal  Ridges  on  the  Flanks. 

.2.  Monoclinal  Ridges  only. 

3.  Inclined  Plateaus. 

III.— UINTA  STRUCTURE. 

Primary  topographic  form.  Plateau  with  rounded  summit  and  abrupt 
shoulders  on  the  flank. 


22  THREE  GEOLOGICAL  PROVINCES. 

Concomitant  forms :  1.  Subsidiary  Plateaus. 

2.  Projecting  Ridges. 

3.  Axial  Peaks. 

4.  Flanking  Peaks. 

5.  Interrupted  Monoclinal  Ridges. 

IV.— KAIBAB  STRUCTURE. 

Primary  topographic  form.     Plateau  with  angular  outlines. 
Concomitant  forms :  1.  Cliff's  of  Displacement. 

2.  Slopes  of  Displacement 

3.  Interrupted  Monoclinal  Ridges  on  the  .Flanks. 

4.  Monoclinal  Ridges  with  Plateau  Carried  Away. 

5.  Projecting  Ridges. 

6.  Cliffs  of  Erosion. 

7.  Buttes. 

8.  Cameo  Mountains. 

V.— BASIN  RANGE  STRUCTURE. 

Primary  topographic  form.     Monoclinal  ridges  of  displacement. 
Concomitant  forms :  1.  Monoclinal  ridges  on  the  back. 

VI.— ZONES  OF  DIVERSE  DISPLACEMENT. 
Topographic  form.     Irregular  hills. 

MOUNTAINS   COMPOSED    I¥   WHOLE   OR    IN    PART   OF   EX- 

TRAVASATED  MATERIAL. 

VIL— TABLE  MOUNTAIN  STRUCTURE. 

VIIL— UINKARET  STRUCTURE. 

IX.— TU-SHAR  STRUCTURE. 

X.— VOLCANIC  STRUCTURE. 

XI.— HENRY  MOUNTAIN  STRUCTURE. 


MONOCLINAL  RIDGES.  23 


GEOGRAPHIC   STRUCTURE   GF   THE   BASIN  PROVINCE. 

•. 

In  this  province  that  orographic  type  which  I  have  described  as  the 
Basin  Range  structure  prevails. 

In  the  consideration  of  the  structure  of  these  ridge  like  mountains,  it  is 
necessary  to  distinguish  clearly  the  two  more  important  elements  involved, 
viz,  that  of  the  metamorphic  and  unaltered  sedimentary  formations,  and 
that  of  the  eruptive  beds. 

The  former  appear  in  simple  monoclinal  ridges  of  displacement,  but 
the  extravasated  material  may  occupy  any  position  in  relation  to  the  simple 
ridges ;  sometimes  it  is  found  appearing  on  the  flanks,  sometimes  burying 
portions  of  the  ranges,  sometimes  extending  in  subequal  masses  in  trans- 
verse or  oblique  directions  to  the  ridges  proper,  and  in  many  ways  compli- 
cating the  topographic  structure.  It  is  of  the  structure  of  the  monoclinal 
ridges  only  that  I  now  speak.  These  ridges  are  not  residuary  fragments  of 
anticlinal  flexures  eroded  in  intaylio,  for  wherever  the  structure  at  the  foot 
of  the  escarpment  is  not  concealed  by  subaerial  gravels,  the  beds  .seen  at 
the  summit  of  the  ridge,  or  known  to  belong  to  a  still  higher  horizon,  appear 
again  at  the  foot  of  the  escarped  face,  showing  that  they  have  been  thrown 
to  that  position  by  a  fault.  The  ridges  themselves  occupy  the  place  of  max- 
imum upheaval.  In  the  summer  of  1870  I  had  some  opportunity  to  examine 
a  few  of  these  ridges  while  oil  a  trip  from  Salt  Lake  City  to  Fillmore,  Bea- 
ver, and  Saint  George,  in  Utah.  In  the  winter  of  1871-72,  I  spent  a  few 
weeks  studying  the  mountains  west  of  the  Rio  Virgen,  and  again  in  1873 
while  engaged  in  prosecuting  some  ethnographic  studies  I  visited  many 
points  in  Western  Utah,  Nevada,  and  Southern  California,  making  cursory 
examinations  of  mountain  structure  on  my  way;  but  Mr.  G.  K.  Gilbert, 
while  engaged  as  geologist  of  the  Wheeler  expedition,  made  a  much  more 
thorough  study  of  this  region.  In  his  report  of  the  geology  of  that  region 
for  1872,  and  published  in  1874,  page  50,  under  the  head  of  "Mountain 
Building/'  Mr.  Gilbert  presents  a  "diagram  of  generalized  mountain  sections 
discounting  denudation,"  which  I  reproduce  (Fig.  7),  preserving  his  lettering. 


24 


THREE  GEOLOGICAL  PROVINCES. 


In  explanation  of  the  diagram  Mr.  Gilbert  remarks: 
"The  sections  accumulated  by  our  geological  observers  admit  of  the 
following  classifications: 

A  B  C  D  E  F 


"1.  Faulted  nionoclinals  occur,  in  which  the  strata  on  one  side  of  the 
fault  have  been  lifted,  while  those  on  the  opposite  side  either  do  not  appear 
£A),  or  (less  frequently)  have  been  elevated  a  less  amount  (B).  Two-thirds 
of  the  mountain  ridges  can  be  referred  to  this  class. 

"2.  Other  ridges  are  uplifts  limited  by  parallel  faults  (C),  and  to  these 
may  be  assigned  a  few  instances  of  isolated  synclinals  (D),  occurring  under 
circumstances  that  preclude  the  idea  that  they  are  remnants  omitted  by 
denudation. 

"3.  True  anticlinals  (E)  are  very  rare,  except  as  local,  subsidiary  fea- 
tures, but  many  ranges  are  built  of  faulted  and  dislocated  rock  masses  (F), 
with  an  imperfect  anticlinal  arrangement. 

"Not  only  is  it  impossible  to  formulate  these  features,  by  the  aid  of  any 
hypothetical  denudation,  in  such  a  system  of  undulations  and  foldings  as  the 
Messrs.  Rogers  have  so  thoroughly  demonstrated  in  Pennsylvania  and  Vir- 
ginia, but  the  structure  of  the  Basin  Range  system  stands  in  strong  contrast 
to  that  of  the  Appalachians.  In  the  latter,  corrugation  has  been  produced 
commonly  by  folding,  exceptionally  by  faulting;  in  the  former,  commonly 
by  faulting,  exception "  '-Hy  by  flexure.  In.  the  latter,  few  eruptive  rocks  occur; 
in  the  former  volcanic  phenomena  abound,  and  are  intimately  associated  with 
ridges  of  upheaval.  The  regular  alternations  of  curved  anticlinals  and  syn- 
clinals of  the  Appalachians  demand  the  assumption  of  great  horizontal  dimi- 
nution of  the  space  covered  by  the  disturbed  strata,  and  suggest  lateral 
pressure  as  the  immediate  force  concerned;  while  in  the  Basin  Ranges,  the 
displacement  of  comparatively  rigid  bodies  of  strata  by  vertical  or  nearly 
vertical  faults  involves  little  horizontal  diminution,  and  suggests  the  appli- 
cation of  vertical  pressure  from  below." 

Thus  a  characteristic  range  of  this  country  is  the  edge  of  a  great  block 


GEOGRAPHIC  STRUCTURE  OF  THE  PLATEAU  PROVINCE.  25 

upheaved  by  the  production  of  a  fault  and  part  passu  with  the  upheaval, 
eroded  into  irregular  forma  and  modified  by  flows  of  eruptive  matter  from 
beneath.  While  this  is  the  general  structure  throughout  the  region  under 
consideration,  there  are  many  exceptions,  as  indicated  by  Mr.  Gilbert.  Of 
especial  interest  are  the  "uplifts  limited  by  parallel  faults  (G),  and  to  these 
maybe  assigned  a  few  instances  of  isolated  synclinals  (D),  occurring  under 
circumstances  that  preclude  the  idea  that  they  are  remnants  omitted  by 
denudation,"  and  the  "many  ranges  built  of  faulted  and  dislocated  rock- 
masses  (F)  with  an  imperfect  anticlinal  arrangement." 

Perhaps  the  latter  are  what  I  have  called  Zones  of  Diverse  Displace- 
ment. 

In  the  northern  portion  of  the  province  other  modifications  of  the  gen- 
eral structure  seem  to  appear.  Mr.  King,  in  the  third  volume  of  the  "Geo- 
logical Survey  of  the  Fortieth  Parallel,"  page  451,  says:  "These  low  mount- 
ain chains  which  lie  traced  across  the  desert  with  a  north  and  south  trend 
are  ordinarily  the  tops  of  folds  whose  deep  synclinal  valleys  are  filled  with 
Tertiary  and  Quaternary  detritus." 

That  there  should  be  exceptions  to  the  general  type  of  structure  in  this 
province  is  not  strange,  for  similar  exceptions  occur  in  each  of  the  other 
provinces,  as  will  appear  hereafter;  but  I  have  myself  seen  no  true-  anticlinal 

mountains  in  the  Basin  Province. 

\ 

The  mountains  of  eruptive  origin  in  this  province  are  chiefly  accessory 
masses  to  the  simple  ridges  of  upheaval,  and  so  far  as  my  observations 
extend,  are  of  the  Tu-shar  type. 

OROGRAPHIC  STRUCTURE  OF  THE  PLATEAU  PROVINCE. 

In  the  Plateau  Province  the  Kaibab  structure  prevails,  but  other  types 
of  structure  are  found.  The  Uinta  Range,  which  furnishes  the  type  for  the 
Uinta  structure  is  found  within  this  province,  and  a  number  of  simple  anti- 
clinals  have  been  discovered ;  we  have  also  found  many  Zones  of  Diverse 
Displacement. 

The  mountains  of  eruptive  origin  are  of  all  the  types  above  mentioned ; 
table  mountains  have  been  observed  in  the  region  drained  by  the  Grand, 
White,  and  Yampa  Rivers.  Pilot  Butte  has  already  been  mentioned,  and 


26  THREE  GEOLOGICAL  PROVINCES. 

other  mountains  of  this  type  are  found  m  the  Sevier  district  The  Uinkaret 
Mountains,  which  have  been  t  :ken  as  a  type  of  structure,  are  on  the  north 
side  of  the  Grand  Canon  of  the  Colorado.  San  Francisco  Mountain  and 
other  mountains  in  that  vicinity  are  known  to  be  of  this  structure,  but  this 
great  group  of  mountains,  of  which  San  Francisco  Mountain  is  the  culmi- 
nating peak,  has  not  been  sufficiently  studied  to  enable  us  to  characterize 
them.  The  Navajo  Mountain,  Sierra  la  Sal,  and  others  in  this  region  are 
knoAvn  to  be  of  the  Henry  Mountain  type. 

The  principal  number  of  important  peaks  and  great  mountain  masses 
of  the  Plateau  Province  are  divided  about  equally  between  the  last  two 
classes.  Some  mountains  of  the  Tu-shar  structure  are  found  in  the  Sevier 
district.  Volcanic  cones  are  found  in  great  numbers  throughout  the  south- 
ern portion  of  the  province. 

GEOGRAPHIC  STRUCTURE  OF  THE  PARK  PROVINCE. 

The  great  mountain  masses  of  the  Park  Province,  especially  those  to 
the  north  standing  about  the  South,  Middle,  and  North  Parks,  which  I  have 
myself  seen,  are  composed  of  metamorphic  crystalline  schists.  It  would 
appear  that  these  schists  were  metamorphosed  antecedent  to  the  deposition 
of  the  Paleozoic,  Mesozoic  and  Cenozoic  rocks,  which  are  found  in  many 
places  resting  unconformably  upon  them  ;  for  all  these  later  sedimentary 
beds  contain  to  a  greater  or  less  extent  conglomerates  which  are  composed 
of  fragments  of  metamorphic  materials  resembling  those  of  the  principal 
mountain  masses ;  and  it  further  appears  from  my  brief  studies  that  this 
series  of  rocks  was  profoundly  plicated,  perhaps  on  the  Appalachian  type, 
i.  e.,  with  closely  appressed  folds,  and  this  also  prior  to  the  deposition  of  the 
upper  sediments.  Through  Paleozoic  and  Mesozoic  times  minor  changes  of 
level  have  occurred,  now  lifting  the  area  above  the  sea,  now  submerging  it, 
so  that  many  gentle  unconformities  are  found  with  an  interrupted  succes- 
sion of  sedimentary  beds.  But  the  last  great  orographic  displacements 
are  represented  by  broad  upheavals  which  appear  to  have  the  structure  of 
the  Uinta  Mountains,  so  far  as  can  be  made  out  from  the  fragmentary 
evidence  left  by  the  great  erosion  to  which  the  country  has  been  subjected 


MB.  MARVINE  ON  THE  PARK  RANGE.  27 

in  late  geological  times.  The  plateau  like  structure  of  these  great  ranges 
with  sedimentaries  dipping  at  high  angles  on  their  flanks,  sometimes  recurved 
so  as  to  cause  inversion  of  the  succession  of  strata,  was  a  feature  which 
made  a  deep  impression  upon  me  in  my  travels  through  this  country  some 
years  ago,  and  in  my  imagination  I  continued  the  later  sedimentary  beds 
in  high  curves  over  these  plateaus,  and  dimly  conjectured  that  tens  of 
thousands  of  feet  had  been  eroded  from  some  of  the  ranges,  and  that  the 
table  or  plateau  like  character  of  the  ranges  was  due  to  some  epoch  of  this 
later  denudation  of  the  ranges  when  they  were  planed  down  to  a  common 
level  under  conditions  which  I  have  explained  in  the  volume  several  times 
quoted.  Such  a  planing  down  occurs  when  the  channels  of  the  eroding 
streams  remain  for  a  great  length  of  time  at  a  general  base  level.  But 
when  I  came  to  study  the  Uinta  Mountains  it  seemed  to  me  that  all  the  facts 
which  I  had  observed  in  the  Park  Province  were  duly  explained  by  sup- 
posing that  that  province  had  the  same  structure  as  that  observed  in  the 
Uinta  Mountains.  Since  my  study  of  that  country  Mr.  Arch.  R.  Marvine 
has  made  a  much  more  thorough  and  careful  survey  of  it  as  one  of  the 
members  of  Dr.  Hayden's  corps.  In  the  report  of  the  United  States  Geo- 
logical and  Geographical  Survey  of  Colorado,  1873,  Hayden,  on  page  188, 
Mr.  Marvine,  under  the  head  of  "  Blue  River  or  Mount  Powell  Group", 
says :  "  The  Park  Range,  after  its  abrupt  rise  from  the  broad  rolling  ridge 
at  the  north,  entirely  changes  in  its  characters.  It  appears  to  be  a  rectangu- 
lar shaped  mountain  mass  cut  into  the  most  profound  amphitheatral  headed 
gorges,  which  are  separated  by  the  most  rugged  and  sharp  saw-like  ridges 
of  rock  imaginable.  The  main  ridge  lies  along  the  southwestern  side  of  the 
mass,  and  from  it  the  valleys  and  their  sharp  separating  ridges  trend  in  a 
general  northeast  direction.  The  northernmost  spur  was  composed  of  a 
very  distinctly  and  evenly  bedded  series  of  schists,  gneisses,  and  granites 
which  had  a  strike  nearly  with  the  ridge,  and  a  dip  of  40°  or  50°  to  the 
southward.  Looked  at  from  the  east,  the  general  impression  is  received 
that  all  of  the  la^ge  ridges  of  the  range  have  a  similar  structure.  These 
rugged  ridges,  in  their  easternmost  portions,  present  a  pretty  uniform  gen- 
eral elevation,  and  as  the  northern  ridge  expands  at  its  end  into  an  even- 
surfaced  table-like  mass  of  rock,  the  impression  is  given  that  all  of  these 


28  THREE  GEOLOGICAL  PROVINCES. 

sharp  ridges  are  but  the  remnants  left  from  the  cutting  away  of  a  plateau 
like  step  which  once  followed  along  the  mountain  face.  These  ridges  also 
end  quite  similarly  along  a  pretty  straight  line,  and  descend  to  rather  a 
uniform  level.  Regarding  now  more  particularly  the  northern  ten  or  fifteen 
miles  of  the  high  range,  which  includes  but  four  or  five  of  the  ridges,  it  is 
observed  that  at  the  base  of  each  steep  end  the  lowered  spur  does  not  con- 
tinue on  as  a  sharp  ridge  but  slopes  off,  a  flat  surfaced,  plateau  like  area, 
descending  gently  eastward.  Since,  upon  the  corresponding  area  at  the 
base  of  the  northernmost  ridge,  great  quantities  of  debris  of  the  Lower 
Cretaceous  sandstones  were  found,  abundantly  proving  that  they  covered 
the  area,  it  appears  that  all  of  these  flattish  areas  either  are  now,  or  have 
comparatively  recently  been,  covered  with  the  same  sandstones.  Such 
features  would  seem  to  indicate  that  the  Cretaceous  had  once  extended  high 
up,  or  quite  over  the  whole  range,  and  that  the  latter,  in  its  upfolding,  had 
received  the  most  pronounced  uplifts  along  certain  well-defined  lines,  the 
intervening  portions  not  being  tilted  up  at  high  angles.  It  is  by  such  a 
process  that  the  front  range,  at  least  from  the  Big  Thompson  to  the  South 
Platte,  has  received  much  of  its  uplift.  Major  Powell  and  Mr.  Gilbert  have 
noticed  similar  folds  in  the  Kaibab  Plateau  and  adjacent  regions  on  the 
great  Colorado  Plateau  of  Northern  Arizona,  though  there  the  sedimentary 
beds  have  not  (by  many  a  thousand  feet)  been  stripped  by  erosion  from  off 
the  underlying  rocks.  It  is  a  form  of  mountain  building  which  I  think  is 
not  uncommon  in  the  West." 

I  am  inclined  to  think  that  the  purposes  of  orology  will  be  better  sub- 
served by  classing  this  structure  as  a  type  distinct  from  that  of  the  Kaibab 
structure,  rather  than  as  a  modification  of  it.  The  general  arching  of  the 
strata  between  the  lines  of  maximum  flexure  or  faulting,  allies  it  some- 
what to  a  true  anticlinal ;  and  so  far  as  my  studies  go  these  lines  of  great- 
est flexure  have  many  more  complexities  than  the  faults  and  monoclinal 
flexures  usually  found  in  the  Plateau  Province.  Hence  I  have  classed  it  as 
a  distinct  type  and  called  it  the  Uinta  structure. 

We  already  know  that  the  spaces  between  the  broad  upheavals,  of 
which  the  ranges  themselves  are  composed,  are  complicated  by  many  anti- 
clinal and  synclinal  flexures  and  by  many  faults,  but  the  whole  structure  of 


STRUCT  OB.- A  L  CHARACTERISTICS  OF  THREE  PROVINCES.  29 

the  parky,  as  these  interspaces  are  often  called,  is  exceedingly  complex,  and 
much  study  is  necessary,  and  a  great  accumulation  of  facts  must  be  obtained 
before  any  safe  generalization  can  be  made  ;  but  these  interspaces  or  park 
areas  are  sometimes  Zones  of  Diverse  Displacement. 

Atlas  Plate  No.  G  presents  a  section  across  three  of  the  great  ranges  of 
the  Park  Province.  This  section  has  been  prepared  for  me  by  Mr.  Marvine. 
The  scale  on  which  it  is  drawn  does  not  admit  of  great  detail,  but  the  gen- 
eral orographic  characteristics  are  well  represented.  In  a  single  section  it 
is  impossible  to  present  all  of  the  facts  upon  which  this  generalization  is 
based.  In  the  quotation  from  Mr.  Marvine  already  given  some  of  the  facts 
on  which  his  opinions  are  based  appear,  and  I  have  myself  seen  patches  of 
sandstone  high  up  on  the  Front  Range  in  the  vicinity  of  Long's  Peak,  and 
also  on  the  northern  end  of  the  Park  Range  in  an  area  of  country  not  visited 
by  Mr.  Marvine,  but  the  shreds  of  evidence  are  too  multifarious  to  be  assem- 
bled here.  The  park  spaces  between  the  great  ranges  are  seen  to  be  com- 
plex in  the  section,  but  the  full  extent  of  this  complexity  could  be  illustrated 
only  by  the  most  full  and  graphic  representation.  Doubtless  when  the 
reports  of  the  several  members  of  the  First  Division  of  the  United  States 
Geological  and  Geographical  Survey  of  the  Territories  are  published,  the 
general  structure  of  this  country  will  be  more  fully  revealed. 

I  have  quoted  Mr.  Marvine  and  discussed  this  subject  with  him  more 
fully  from  the  fact  that  he  and  I  have  visited  many  of  the  same  points. 

I  have  not  myself  studied  the  eruptive  mountains  of  this  province. 

SUMMARY  OF  THE  STRUCTURAL  CHARACTERISTICS  OF 
THE  THREE  PROVINCES. 

The  Basin  Province  is  characterized  by  north  and  south  ranges  that  are 
monoclinal  ridges  of  upheaval,  and  these  monoclinal  ridges  are  separated  by 
stretches  of  subaerial  gravels  that  mask  the  structure  of  the  areas  of  subsi- 
dence. But  while  this  is  the  prevailing  structure,  other  types  are  found. 

In  the  Plateau.  Province  the  Kaibab  structure  is  the  characteristic. 
Here  on  a  grand  scale  the  primary  and  concomitant  forms  are  found;  but 


30  THREE  GEOLOGICAL  PROVINCES. 

Simple  Anticlinals,  the  Uinta  structure,  and  Zones  of  Diverse  Displacement 
are  found  as  exceptional  types. 

In  the  Park  Province  the  Uinta  structure  prevails  and  its  primary  and 
concomitant  topographic  forms  are  grandly  shown.  Doubtless  a  more  thor- 
ough study  of  this  region  will  result  in  the  discovery  of  exceptional  types. 

THESE  PROVINCES  NOT  SEPARATED  BY  WELL  DEFINED 

LINES. 

No  line  of  demarcation  can  be  drawn  between  the  Plateau  Province 
and  the  Park  Province.  There  is  an  irregular  belt  of  country  separating 
the  better  defined  portions  of  the  two  provinces,  which  is  complicated  by 
characteristics  belonging  to  each.  The  Kaibab  structure  of  the  plateaus 
does  not  change  abruptly  into  the  Uinta  structure,  which  prevails  in  the 
latter  province.  In  fact  there  are  many  areas  lying  along  the  border  sepa- 
rating the  two  provinces  which  are  characterized  by  a  great  development 
of  eruptive  beds,  which  serve  to  a  greater  or  less  extent  to  mask  the  oro- 
graphic  structure  of  the  sedimentary  beds. 

In  like  manner  on  the  south  and  west  of  the  Plateau  Province  there  is 
a  belt  of  country  separating  it  from  the  Basin  Province,  itself  forming  a  sub- 
province  of  great  interest.  This  region  has  already  been  the  subject  of  much 
study,  and  although  these  studies  have  not  been  completed,  many  facts  have 
been  discovered  from  which  we  can  with  safety  make  some  important  de- 
ductions. Through  late  Mesozoic  and  earlier  Tertiary  times  there  was  an 
old  shore  line  here,  now  retreating  eastward,  now  advancing  westward.  It 
is  a  region  of  many  movements  by  faulting  and  flexing,  and  during  these 
movements,  in  Tertiary  times  at  least,  many  lavas  were  poured  out,  so  that 
we  have  many  unconformities  both  abrupt  and  gentle,  many  shore  deposits, 
many  faults  and  flexures  and  many  beds  of  eruptive  matter.  But  the  north- 
ern portion  of  the  Basin  Province  is  separated  geographically  as  well  as 
geologically  from  the  Plateau  Province  by  the  Wasatch  Mountains  which 
constitute  a  distinct  geographic  system;  but  geologically  it  is  but  a  northern 
extension  of  the  intervening  belt  which  I  have  already  described,  charac- 
terized as  distinct  from  that  by  the  fact  that  the  movements  of  displacement — 


ZONES  OF  DIVERSE  DISPLACEMENT.  31 

faulting  and  flexing- — were  on  a  grander  scale  and  as  a  consequence  of  this 
greater  displacement,  the  accumulations  of  sediments  are  greater  and  the 
unconformities  more  apparent  and  complex.  Another  consequence  of  the 
greater  displacement  is  that  the  deep  lying  metamorphic  rocks  are  brought 
up  and  .exposed  by  denudation,  so  that  extensive  groups  of  crystalline  schists 
and  quartzites  appear. 

This  geographic  district,  the  Wasatch  Subprovince,  terminates  on  the 
south  at  Mount  Nebo,  and  is  quite  distinct  geographically  as  well  as  geologi- 
cally from  the  subprovince  to  the  southward,  which  may  be  termed  the 
Sevier  and  Rio  Virgen  Sub-province. 

Thus  the  Wasatch  and  Sevier  districts  separate  the  Basin  and  Plateau 
Provinces,  not  by  the  introduction  of  new  types  of  structure,  but  by  a  com- 
bination of  the  types  observed  on  either  hand  and  being  complicated  by 
conditions  consequent  on  their  forming  for  a  long  time  the  shore  line  be- 
tween the  two.  In  the  Sevier  portion  of  the  belt  the  Kaibab  structure  pre-  . 
vails,  while  in  the  Wasatch  portion  the  Basin  Range  structure  prevails. 

The  great  Wasatch  Range  presents  a  bold  front  to  the  west  due^  in  a 
general  way  to  a  great  fault  or  rather  a  series  of  faults  such  as  I  have  de- 
scribed as  occurring  in  the  Basin  Ranges;  but  on  the  east  or  back  slope  of 
the  range  the  structure  is  complex.  An  irregular  belt  of  country  stretching 
from  the  crest  of  the  mountains  eastward  many  miles  is  faulted  and  flexed 
in  many  ways. 

In  the  northeast  angle  formed  by  the  Wasatch  and  Uinta  Mountains 
there  is  a  long  but  narrow  and  irregular  zone  stretching  toward  the  north- 
east from  the  head- waters  of  the  Bear  River.  Sulphur  Creek  drains  a  part 
of  this,  and  the  well  known  Bear  River  coal  lands  are  found  in  the  district. 
From  Aspen  to  a  point  near  Carter,  the  Union  Pacific  Railroad  runs  along 
the  eastern  border  of  the  belt.  Its  extension  in  either  direction  beyond  the 
points  indicated  are  unknown  to  me.  This  belt  also  exemplifies  what  I 
have  called  Zones  of  Diverse  Displacement,  and  the  general  effect  is  upheaval. 
The  belt  seems  to  have  been  broken  into  very  irregular  blocks  by  lines  of 
faulting  or  flexure  which  so  far  as  my  observation  has  extended  preserve 
no  law  of  direction. 

The  blocks  into  which  the  country  has  been  broken  have  been  tilted, 


32  THREE  GEOLOGICAL  PROVINCES. 

greatly  sometimes,  sometimes  turned  quite  on  edge,  and  even  in  some  cases 
reversed.  One  of  these  blocks  standing  on  edge  afforded  Professor  Meek 
the  opportunity  to  make  his  section  on  Sulphur  Creek  published  in  Dr.  Hay- 
den's  Report  on  the  Geological  Survey  of  Montana,  Idaho,  Wyoming,  and 
Utah,  1872.  Professor  Meek  evidently  recognized  the  difficulty  of  correlat- 
ing the  strata  in  that  section  with  those  outcropping  elsewhere  in  the  dis- 
trict. I  mention  these  excessively  complex  zones  without  attempting  to 
explain  them.  Some  student  of  geology  will  eventually  find  here  a  subject 
rich  in  results. 

SUMMARY  OUTLINE  OF  THE  HISTORY  OF  THE  THREE 
PROVINCES  DURING  CENOZOIC  TIME. 

In  the  latter  part  of  Mesozoic  time  the  greater  part  of  the  .Basin  Province 
was  dry  land.  The  Plateau  Province  was  an  open  but  shallow  sea.  In 
the  Park  Province  a  chain  of  islands  extended  to  the  south.  The  Cenozoic 
time  was  inaugurated  by  a  series  of  movements,  which,  continued  to  the 
present  time,  have  produced  the  topographic  features  now  observed.  This 
part  of  the  crust  of  the  earth,  and  I  mean  by  the  term  "  crust"  simply  that 
portion  of  the  earth  which  we  are  able  to  study  by  actual  observation  in 
truncated  folds  and  eroded  faults — this  portion  of  the  crust,  then,  was  gradu- 
ally broken  and  contorted.  The  Plateau  and  Park  Provinces  were  cut  off 
from  the  sea,  and  great  bodies  of  fresh  water  accumulated  in  the  basins, 
while  to  the  east  in  the  region  of  the  Great  Plains,  in  earlier  Tertiary  times 
at  least,  there  was  an  open  sea.  Slowly  through  Cenozoic  times  the  outlines 
of  these  lakes  were  changed,  doubtless  in  two  ways :  first,  by  the  gradual 
displacement  of  the  rock  beds  in  upheaval  and  subsidence  here  and  there  ; 
and,  second,  by  the  gradual  desiccation  due  to  the  filling  up  of  the  basins  by 
sedimentation  and  the  erosion  of  their  barriers  ;  and  the  total  result  of  this 
was  to  steadily  diminish  the  lacustrine  area.  But  the  movements  in  the  dis- 
placement extended  over  the  Basin  Province,  for  that  region  was  then  a 
comparatively  low  plain,  constituting  a  general  base  level  of  erosion  to 
which  that  region  had  been  denuded  in  Mesozoic  and  early  Tertiary  time 
when  it  was  an  area  of  dry  land ;  for  I  think  that  from  the  known  facts  we 
may  reasonably  infer  that  the  Basin  Ranges,  though  composed  of  Paleozoic 


THE  THREE  PROVINCES  DURING  CENOZOIC  TIME.  33 

and  Eozoic  rocks,  are,  as  mountains,  of  very  late  upheaval.  For  some  pur- 
poses, and  in  broad  generalization,  erosion  furnishes  a  valuable  measure  of 
geological  times.  A  mountain,  as  a  mountain,  is  comparatively  ephemeral. 
The  evidence  of  this  is  found  on  every  hand  as  we  study  the  Rocky  Mount- 
ain region.  There  can  be  no  conclusion  reached  from  reasoning  on 
geological  data  more  certain  than  that  the  Uinta  upheaval  began  at  the  close 
of  Mesozoic  time,  and  has  continued  intermittently  near  to  the  present,  and 
during  that  time  this-  upheaval  has  suffered  a  degradation  in  areas  of  maxi- 
mum erosion  of  no  less  than  30,000  feet;  and  there  is  evidence  also  which 
leads  to  the  conclusion  that  the  conditions  for  great  erosion  were  not  per- 
sistently maintained  during  this  time.  I  have  already  stated  that  the  Basin 
Ranges  occupy  the  area  of  maximum  upheaval,  and  they  are  monoclinal 
ridges.  Had  these  ridges  been  upheaved  greatly  beyond  their  present 
altitudes  it  is  manifest  that  erosion  would  have  carried  them  far  back  from 
the  lines  of  faults,  a  condition  not  found  to  obtain. 

In  the  erosion  of  these  ridges,  as  an  independent  subject  of  study,  the 
geologist  is  impressed  with  the  magnitude  of  the  work  which  has  been  per- 
formed by  atmospheric  agencies.  It  appears  that  each  ridge  is  but  a  small 
residuary  fragment  of  the  great  inclined  block,  and  the  interrange  spaces  are 
filled  with  clays,  sands  and  gravels,  the  waste  of  these  blocks,  in  such  a 
manner  as  to  bury  the  underlying  rocks  over  broad  areas ;  and  whether  we 
consider  the  amount  which  has  been  lost  from  the  blocks  or  the  amount 
which  has  been  accumulated  in  the  valleys,  the  loss  here  or  the  gain  there, 
this  transferred  material  is  very  great.  It  is  worthy  of  remark  that  over 
much  of  the  area,  the  deposit  of  this  transferred  material  in  the  valleys  was 
subaerial,  but  in  the  northwestern  portion  of  the  province  it  was  lacustrine. 

But  when  we  compare  the  erosion  which  these  inclined  blocks  have 
suffered  with  that  of  many  of  the  great  blocks  in  the  Plateau  Province  of 
the  Kaibab  structure,  or  with  that  of  the  Uinta  uplift,  or  with  the  great 
uplifts  in  the  Park  Province,  the  erosion  of  the  Basin  Range  ridges  sinks 
into  insignificance.  And  when  we  consider,  further,  that  the  erosion  in  the 
Plateau  and  Park  Provinces  which  we  are  able  to  study  has  all  been  per- 
formed during  Cenozoic  time,  and  that  the  conditions  of  maximum  erosion 

were  but-  intermittent  during  that  time,  we  are  forced  to  the  conclusion  that 
3  P  G 


34  T11IJEE  GEOLOGICAL  PKOVINCES. 

the  conditions  for  great  erosion  now  found  in  the  Basin  Ranges  have  existed 
but  for  a  short  period,-*-,  e.,  the  blocks  were  certainly  not  upheaved  ante- 
cedent to  Cenozoic  time ;  and  it  would  seem  probable  that  it  must  have  been 
in  late  Tertiary. 

It  seems  proper  to  add  here  a  remark  concerning  certain  conditions  of 
erosion,  though  I  have  elsewhere  discussed  the  subject  more  fully. 

The  lesser  or  greater  rapidity  of  erosion  depends  chiefly  upon  three 
conditions:  first,  elevation  above  the  base  level  of  erosion;  second,  the 
induration  of  the  rocks ;  and,  third,  the  amount  of  rain  fall.  But  erosion 
does  not  increase  in  ratio  with  the  increase  of  the  precipitation  of  moisture, 
for  increasing  moisture  serves  to  increase  the  protection  derived  from 
vegetation. 

Nor  does  induration  greatly  preserve  rocks  from  erosion,  for  on  most 
exposures  the  action  of  the  elements  in  disintegrating  the  rocks  is  in  excess 
of  the  power  of  the  streams  to  carry  the  material  away.  The  exceptional 
exposures  are  found  on  steep  slopes ;  yet  the  difference  in  the  induration  of 
beds  has  an  effect  as  seen  in  the  minor  or  concomitant  forms  of  all  mountain 
regions.  The  principal  factor  in  maximum  erosion  is  elevation  above  the 
base  level,  and  the  power  of  erosion  increases  in  geometric  ratio  with  the 
elevation.  The  power  of  the  streams  to  transport  the  material  of  erosion 
is  increased  in  geometric  ratio  and  the  power  of  the  water  in  corrasion  is  in 
like  manner  increased ;  and  the  corrasion  of  deep  channels  by  rapid  streams 
filled  with  sands,  gravels  and  bowlders  produces  another  condition  of  surface 
favorable  to  general  degradation — that  is,  the  walls  of  these  deep  channels 
are  broken  down  by  gravity,  which  is  further  increased  by  an  undermining 
process  where  harder  and  softer  beds  alternate.  With  these  facts  in  view, 
we  need  not  enter  into  a  consideration  of  the  difference  of  texture  or  indu- 
ration of  the  rocks  of  the  Plateau  and  Park  Provinces  and  those  of  the 
Basin  Province ;  but  we  may  remark  that  of  the  30,000  feet  eroded  from 
the  Uinta  uplift,  more  than  16,000  feet  were  of  beds  of  Paleozoic  Age,  and 
with  a  texture  as  firm  as  the  rocks  of  the  Basin  Ranges. 

It  is  manifest  that  the  result  of  all  these  movements  of  displacement  in 
the  three  provinces  was  general  upheaval.  But  this  upheaval  in  the  three 
provinces  was  unequal ;  it  was  great  in  the  Basin  Province,  greater  in  the 


THE  DBAINAGE  REVERSED.  35 

Plateau  Province,  and  greatest  in  the  Park  Province.  The  Basin  Province 
was  already  above  the  sea  level,  but  a  comparatively  low  plain.  In  such  a 
condition,  erosion  would  be  slight;  and  as  the  ranges  were  lifted,  the  mate- 
rial derived  from  them  was  deposited  in  the  valleys,  and  it  is  probable  that 
no  considerable  amount  was  transported  beyond  the  province  into  the  sea, 
and  the  general  uplift  of  the  province  was  little  or  no  greater  than  the 
change  from  that  of  the  low  plain  near  the  sea  level  to  its  present  elevation — 
that  is,  the  Basin  Province  as  a  body  is  not  the  result  of  the  difference  be- 
tween erosion  and  elevation ;  but  the  ranges  themselves  do  thus  mark  the 
difference  between  erosion  and  elevation.  That  which  was  taken  from  the 
mountains  was  added  to  the  valleys.  Much  of  the  Plateau  Province  was 
still  an  area  of  rapidly  accumulating  sediments  long  into  Tertiary  time ; 
but  at  last  the  movements  which  began  at  the  commencement  of  Tertiary 
time  succeeded  in  bringing  the  whole  area  not  .only  above  the  level  of  the 
sea,  but  above  the  general  level  of  the  Basin  Province  itself;  so  that  while 
the  Basin  Province  was  drained  into  the  Plateau  Province  in  earlier  Tertiary 
time,  in  late  Tertiary  time  the  drainage  was  reversed,  and  the  streams  of 
the  Plateau  Province  found  their  way  to  the  sea  by  passing  through  the 
Basin  Province,  and  many  of  them,  especially  those  in  the  Sevier  and 
Wasatch  regions  which  head  along  the  old  shore  line,  are  now  drained  into 
the  basins  which  characterize  the  province  thus  designated. 

It  is  the  opinion  of  Mr.  llowell,  and  I  believe  also  that  of  Captain 
Dutton,  that  this  drainage  was  in  some  cases  reversed  along  the  very  channels 
occupied  by  the  ancient  streams  which  ran  from  the  Basin  Province  into 
the  Plateau  lakes.  In  the  Park  Province  the  general  upheaval  was  still 
greater,  and  the  Colorado  River,  which  empties  into  the  Gulf  of  California, 
heads  in  the  very  heart  of  the  Park  Province  and  drains  the  greater  part  of 
the  Plateau  Province  by  carrying  its  waters  across  the  Basin  Province. 
While  the  general  surface  of  the  last  two  mentioned  provinces  was  in 
Mesozoic  time  not  above  the  level  of  the  sea,  at  the  present  time  the  general 
surface  is  from  four  to  fourteen  thousand  feet  above  the  sea  level ;  but  there 
are  portions  now  marked  by  great  ranges  which  have  been  upheaved  twenty 
and  thirty  thousand  feet ;  but  these  portions  during  the  progress  of  upheaval 
suffered  denudation,  and  a  part  at  least  of  the  material  thus  denuded  was 


36  THEEE  GEOLOGICAL  PROVINCES. 

not  carried  away  to  the  sea  but  was  deposited  in  fresh  water  basins.  But 
at  last  these  fresh  water  basins  themselves  were  drained  and  their  beds 
faulted  and  flexed  and  eroded,  and  their  sites  are  now  found  marked  by 
broad  stretches  of  bad-lands. 

I  speak  of  an  open  sea  to  the  east  of  the  Park  Mountains,  where  now 
the  Great  Plains  stretch  in  broad  expanse.  That  there  was  a  sea  or  arm  of 
the  sea  here  is  manifest,  for  I  have  collected  marine  Tertiary  fossils  of 
Vicksburgh  types  in  several  places  east  of  Denver;  but  from  my  exceed- 
ingly brief  studies  in  that  region,  merely  as  a  passing  traveler,  I  can  only 
say  that  the  region,  though  simple  in  its  topographic  features,  is  indeed 
complex  in  its  geological  structure. 

Throughout  this  great  area,  from  the  eastern  slope  of  the  Park  Moun- 
tains on  the  east  to  the  eastern  slope  of  the  Sierra  Nevada  on  the  west,  and 
from  the  sources  of  the  Green  and  Shoshoni  Rivers  on  the  north  to  the 
San  Francisco  Mountains  on  the  south,  the  whole  region  is  broken,  flexed, 
and  contorted  along  innumerable  lines.  But  the  great  structure  lines  have 
a  north  and  south  trend ;  the  ranges  of  the  Basin  Province  run  from  north 
to  south  ;  the  great  faults  of  the  Plateau  Province  also  run  north  and  south, 
and  the  Park  Ranges  have  a  north  and  south  trend.  But  these  general 
outlines  are  broken  by  oblique  and  transverse  displacements,  usually  of  a 
minor  magnitude,  though  in  some  cases,  as  in  the  Uinta  Mountains,  these 
transverse  displacements  assume  as  great  proportions  as  the  north  and  south 
flexures  and  faults.  While  the  whole  region  is  exceedingly  complex  by 
displacement,  it  is  also  exceedingly  complex  by  reason  of  the  unconformity 
of  its  sedimentary  beds.  And  all  this  complexity  is  greatly  increased  by 
reason  of  the  floods  of  lava  which  have  been  poured  out  here  and  there 
over  the  entire  area,  and  now  and  then  through  Cenozoic  up  to  the  present 
time.  And  all  these  floods  of  lava,  all  these,  thousands  of  eruptive  moun- 
tains, thousands  of  mesa  sheets,  thousands  of  volcanic  cones,  testify  to  a 
period  of  great  volcanic  activity  while  the  region  was  in  fact  a  great  conti- 
nental area,  thus  contradicting  the  generalization  which  has  obtained  in  some 
quarters  that  volcanic  activity  is  adjacent  to  the  sea.  And  further,  very 
much  of  this  volcanic  activity  has  been  exhibited  since  the  desiccation  of 
the  lakes. 


OHA.PTBR    II. 


SEDIMENTARY  GROUPS  OF  THE  PLATEAU 

PROVINCE. 

We  turn  now  to  a  consideration  of  the  Plateau  Province.     Throughout 
its  extent  it  is  -traversed  by  profound  gorges   or  canons  ;  high  cliffs  are 
found ;  long  ridges  and  lone  buttes  are  seen,  all  presenting  escarpments 
unclad  with  vegetation  where  the  geological  structure  is  plainly  revealed, 
and  it  is  nowhere  concealed  to  any  important  extent  by  subaerial  gravels, 
river  deposits,  deep  soil,  or  rich  vegetation.     The  whole  region  has  been  flexed 
and  faulted  on  a  vast  scale  ;  the  flexures  are  truncated  by  erosion,  and  the 
faults  are  crossed  by  canons  and  lines  of  cliffs  ;  and  thus  by  a  combination 
of  circumstances  the  whole  region  is  an  open  book  to  the  geologist,  revealing 
a  wonderfully  complicated  structure  and  a  grand  succession  of  formations. 
Accumulations  of  sediments  may  be  studied  of  Cenozoic,  Mesozoic,  and 
Paleozoic  Ages,  each  represented  by  formations  that  are  measured  by  thou- 
sands of  feet.     In  the  hearts   of  the  mountains  and  depths  of  the  canons 
Eozoic  rocks  are  found  ;  on  the  mesas  and  elevated  valleys  sheets  of  lava 
have  been  spread;  and  naked  volcanic  cones  crown  the  geological  series.    A 
general  section  of  the  sedimentary  beds  alone   sums  up  a  total  of  nearly 
60,000  feet,  and  the  relations  of  the  groups  into  which  they  can  be  divided 
can  be  determined  with  a  certainty  rarely  attainable  in  the  eastern  portion 
of  the  United  States.     When  we  group  these  beds  in  such  a  manner  as  the 
structural  geology  demands  we  have  a  series  of  groups  or  succession  of 
formations  separated  by  epochs  of  change,  producing  unconformities  or 
resulting  in  extensive  stratigraphic  peculiarities,  and  in  constructing  a  'gen- 
eral section  of  this  country  this  natural  series  cannot  be  ignored  without 

37 


38      SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

greatly  distorting  the  facts.  But  a  section  thus  arranged  presents  a  series 
of  limestones,  shales,  sandstones  and  conglomerates  totally  unlike  that 
which  has  been  established  in  the  New  York  and  Appalachian  Province  or 
in  the  Valley  of  the  Mississippi.  Again  in  several  of  the  groups  we  dis- 
cover the  remains  otf  rich  faunas  and  floras,  but  the  series  of  fossils  belonging 
to  any  of  the  natural  groups  in  the  Plateau  Province  is  unlike  that  of  any 
group  or  formation  in  the  earlier  studied  rocks  of  the  east ;  either  entirely 
new  series  are  found  or  the  old  types  are  regrouped  so  as  to  present  a  new 
aspect.  Hence  it  would  be  manifestly  absurd  to  introduce  into  this  newly 
studied  province  the  nomenclature  adopted  in  those  provinces  which  had 
been  previously  studied,  as  it  would  involve  the  necessity  of  explaining  in 
each  case  that  the  name  was  used  with  a  new  meaning,  and  that  the  adop- 
tion of  the  older  names  was  intended  simply  to  express  the  opinion  that  the 
group  to  which  it  was  given  should  be  referred  to  some  period  in  the  geo- 
logical time  scale  about  the  same  as  that  held  by  the  group  to  which  the 
name  was  originally  applied ;  and  this  would  involve  the  re-adjustment  of 
the  names  from  time  to  time  on  the  collection  of  new  suites  of  fossils.  While 
it  does  not  seem  possible  to  consider  a  particular  sandstone  or  limestone,  or 
a  particular  group  of  strata  as  identical  with  or  closely  similar  to  one  in 
New  York  or  Illinois,  this  does  not  preclude  the  possibility  of  establishing  a 
general  synchronism.  The  Cenozoic,  Mesozoic  and  Paleozoic  Ages  seem 
to  l)e  as  well  defined  as  elsewhere,  and  in  each  age  there  are  formations 
which  are  earlier  or  later,  but  the  details  of  this  general  synchronism  can 
only  be  discovered  after  a  far  more  thorough  study  of  the  paleontology  of 
the  province  has  been  made. 

The  conclusions  thus  stated  have  been  reached  after  a  stud}'  of  the 
province  which '  has  occupied  the  greater  part  of  the  last  eight  years. 
During  the  earlier  years  I  attempted  here  to  find  the  formations  of  the 
east,  or  at  least  formations  corresponding  to  them,  and  thus  years  of  study 
were  in  part  fruitless  for  that  reason.  I  then  determined  if  possible 
to  discover  the  natural  series  of  the  province  itself  independent  of 
other  regions,  and  the  general  section  below  is  the  result.  Perhaps,  from 
a  priori  reasons,  I  should  have  commenced  with  this  plan.  The  supposi- 
tion that  at  the  same  time  sediments  should  have  been  carried  into  the 


NAMES  OF  THE  GEOUPS.  39 

Colorado  sea  similar  to  those  in  the  New  York  sea,  is  not  warranted  by  a 
study  of  the  deposits  now  forming  in  existing  seas.  The  Hudson  River 
carries  a  very  different  deposit  into  the  Atlantic  Ocean  from  that  carried  by 
the  Colorado  River  into  the  Gulf  of  California.  Nor  should  we  expect  that 
the  faunas  or  floras  of  regions  so  widely  separated  should  be  the  same  or 
closely  similar.  In  the  earlier  times,  which  we  study  as  geologists,  there 
seem  to  have  been  physical  conditions  in  the  two  regions  as  widely  differing 
as  those  of  the  present.  The  Cenozoic  formations  of  the  plateaus  are  lacus- 
trine ;  the  Cenozoic  formations  of  the  Atlantic  slope  are  marine.  The  Meso- 
zoic  of  the  plateaus  is  of  great  extent  and  thickness,  while  that  age  is  but 
scantily  represented  on  the  Atlantic  slope.  Nor  do  the  Paleozoic  forma- 
tions exhibit  a  close  similarity. 

The  names  which  I  have  selected  for  the  groups  are  geographic,  as 
such  a  system  admits  of  easy  interpolation,  and  the  localities  serve  well  in 
fitting  the  name  to  the  group  and  refer  at  once  to  the  typical  strata.  For 
obvious  reasons  I  should  have  been  pleased  to  have  commenced  with  a 
clean  slate,  selecting  such  localities  as  would  serve  for  the  best  types ;  but 
I  did  not  feel  at  liberty  to  ignore  the  labors  of  geologists  who  had  pre- 
ceded me. 

In  the  Cenozoic  groups  and  the  first  Mesozoic  I  found  great  confusion, 
as  these  groups  had  been  seen  at  many  places,  and  some  of  them  received 
several  names  each ;  and  often  different  groups  were  confounded  by  being 
included  under  one  geographic  name.  With  these  groups  I  have  tried  to 
select  such  localities  as  would  serve  to  fairly  represent  the  groups  and  at 
the  same  time  do  no  injustice  to  other  laborers. 

We  now  append  the  general  section. 


40 


SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 


TABLE  OF  THE  GROUPS  OF  SEDIMENTARY  STRATA  OF 
THE  PLATEAU  PROVINCE. 


Scale  in 
feet. 


2,  000 


4,000 


6,000 


8,  COO 


10,000 


12,  000 


14,  000 


i 


300 


1,800 


2,000 


500 


800 


3,  000 


1,800 


1,800 


2,000 


Groups. 


Bishop  Mt  Conglo 


Brown's  Park. 


Bridger. 


Upper  Green  Rivei 


Lower  Green  River 


Bitter  Creek. 


Point  of  Hocks. 


Salt  Wells. 


Sulphur  Creek. 


Uriconformable  by  i)li< 


.th  underlying  rocks. 


Sandstones,  gravels,  limestones,  concretionary 
and  stratified  flints.  Unconformable  with  all 
underlying  rocks. 


Bad-land  sandstones,  (chiefly  green-sands,)  lime- 
stones, shells— marls, -and  concretionary  and 
stratified  flints. 


Shnles,  often  bituminous;  sandstones  and  lime- 
stones ;  carbonaceous  shales  and  lignitic  coal 
near  the  base. 


Bad-laud  sandstones,  often  with  much  gypsum  ; 
indurated  sandstones;  ferruginous;  shell- 
marls  ;  many  beds  of  carbonaceous  shales  and 
lignitic  coal.  To  the  southward  the  group  is 
composed  of  indurated  sandstones  and  lime- 
stones. Uiicoiiformablc  by  plication  and  ero- 
sion with  the  next. 


Upper  Hogback 
Sandstone. 

Middle  Hogback 
Sandstone. 

Golden  Wall 
Sandstone. 


Sandstones,  usually  indurated, 
sometime  ferruginous,  with 
many  beds  of  carbonaceous 
shales  and  lignitic  coal. 


Sandstones  or  arenaceous  shales;  often  very 
friable,  producing  bad-lands,  with  carbonaceous 
shales  arid  lignitic  coal. 


Black  shales;    occasionally  friable    sandstones 
with  carbonaceous  shales  and  lignitic  coal. 


Henry's  Fork. 


Sandstones,  bad-laud  rocks,  conglomerates,  and 

shales,  with  carbonaceous  slriles  and  lignitic  coal. 


'  Unconformable  by  erosion  with  the  next. 


TABLES  OF  THE  GROUPS. 


41 


MESOZOIC. 

JURA  AND  TRIAS. 

2,000 
4,000 
6,000 
8,000 
10,  000 
12,  000 
14,  000 

i,  aoo 

Flaming 
Gorge. 

l!ad-land  sandstones,  sftnetimes  argillaceous,  with  much  gypsum  ;  massive  sandstones 
and  limestones.    Three  members  of  this  group  deserve  special  mention.     A  bed  of 
limestone  has  been  found  at  the  base  of  the  group  wherever  it  has  been  studied 
varying  from  10  feet  to  200  feet  in  thickness.     In  Southern  Utah  it  caps  an  extensive 
escarpment  known  as  the  White  Cliffs,  and  we  have  called  it  the  White  Cliff  Lime- 
stone.    In  other  localities  a  limestone  more  or  less  arenaceous  is  found  of  about  the 
some  thickness  ;  this  limestone  is  about  midway  in  the  group.     We  have  called  it 
the  Mid-Group  Limestone.  Immediately  underlying!  hi?,  in  more  northern  localities 
a  massive  sandstone  is  found,  from  400  to  600  feet  in  thickness.   Farther  to  the  soutl« 
this  massive  sandstone  is  represented  by  bad-land  sandstones  with  clny  and  gypsum 

"•  '.'•  ••'•:  :;-:}^--  '•••  ~$-:.-K-  A';;. 

x<v=vcvr%d>^ry; 

- 

f^^£^S^S£~g&-f. 

1,100 

White  Cliff. 

Usually  the  entire  group  is  a  massive  obliquely  laminated  sand- 
stone often  of  a  beautiful  white  or  golden  color,  sometimes  red. 
In  a  few  places  rather  heavily  bedded  sandstones  are  found. 

'.  •.'-'-'  :   '   >'  -  -'—  H 

1,  101. 

Vermilion 
Clitf. 

Massive  sandstones  with  ferruginous  layers  and  often  with  thin, 
irregular  beds  of  chcrty  limestone  ;  the  massive  beds  sometimes 
broken  into  thinner  strata. 

:O^~:.  »  '^'•.^•'*-  "  ^-' 

- 

;:>r.VW.-  ?•-'.•  -'--W- 

1 

^SipS& 

1,800 

Shiuarump. 

Upper         Dad-land  sandstones  with  much  gypsum  ;  often  argillaceous  ;  someti-nea 
Shinarump.        indurated  sandstones. 
sliinarump     ^  "ne  rong'cimerate  not  easily  recognized,  toward  the  north,  about  SO 
Connlom-          (eet  '"  thinness,  but  increasing  southward  until  it  attains  200  feet.     It 

erate.             is  foumi  cwP'oeanextensiveescarpmentknownastheShinarumpCliHs. 
Bad-land  sandstones  with   much  gypsum;  sometimes  argillaceous;  in  a 
Lower            few  Places  tney  are  indurated  sandstones  ;  sometimes  unconformable 
Shinarumn        by  erosion  with  the  next.     In  such  places  a  conglomerate  is  found  at 
the  base  composed  of  rounded  and  angular  fragments  of  carboniferous 

ana  IP  loio  o  oa  o  o  w 

8 

o 

N 

o 

§ 

<1 
Pi 

CARBONIFEROUS. 

1,000 

Upper  Au- 
brey. 

Sandstones  and  limestones,  the  latter  cherty.    To  the  north  there  a'e  two  members  of 
this  group;  th»  upper  is  cherty  limestone  from  100  feet  to  200  feet  in  thickness,  which 
we  have  called  the  Bellerophon  Limestone.    The  lower,  the  Tampa  Sandstone,  is 
very  massive,  rarely  showing  evidences  of  stratification  ;  in  some  places  obliquely 
laminated.    Farther  8outhward  cherty  limestones  prevail,  and  the  whole  group  is 
more  minutely  stratified. 

-iiiii   i  i  .   . 

1,000 

Lower  Au- 
brey. 

Sandstones  and  limestones  massively  bedded  or  shaly.    In  some 
localities  sandstones  prevail  and  arc  exceedingly  friable. 

.'•'•'  i  •  i  '>  '.',',•.'  * 

T7l7??7TTyT?^ 

i    i    t  '  i  '  .  __. 

2,000 

Red  Wall. 

Chiefly  limestones.    In  the  Uinta,  Mountains  massive  limestones 
are  separated  by  thin    strata  of  sandstones.     In  the  Grand 
Canon  a  massive  limestone  a  thousand  leet  in  thickness  is 
found,  with  thinner  strata  of  limestone  and  sandstone  beneath. 
In  the  Uinta  Mountains  the  group  is  conformable  with  the  Lo- 
dore  series  and  unconformablo  with  the  Uinta  Sandstone.    In 
the  Grand  Caiion  it  is  conformable  with  the  Tonto  Group. 

j    i      i     i__ 

4(50 

Lodorc. 

Sandstones  and  shales  :  supposed  to  be  the  equivalent  in  the  Uinta  Mountains  to  the 
Tonto  Group  in  the  Grand  Canon. 

12,  500 

Uinta. 

Sandstones;  massive;  thinly  bedded,  and    shales;  ferruginous; 
some  portions  metamorphosed,  becoming  a  quartzite.    Uncon- 
formablo by  extensive  plication  and  erosion  on  the  Red  Creek 
Quartzite. 

U-~d 

- 

-™-  ^j 

- 

v  :  •.-.-   :  -.'  .'  \v-^- 

-•'"'  '  '  "  --^^ 

42  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 


A  quartzite  with  ImruhliMidic  and  micaceous  schists,  all 
urcatl.y  iinpl&atod. 


TABLES  OF  TOE  GROUPS.  43 

BASE    OF   THE    SECTION  IN  THE    GRAND   CANON    OF   THE 

COLORADO. 


I  Base  of  Red  Wall  Group. 


Sandstones  and  shales,  with  a  lew  limestones ;  uncon- 
formable  by  extensive  plication  and  erosion  on  the 
next. 


Sandstones,  shales,  and  a  few  limestones.    On  further 
study  this  group  will  probably  bo  subdivided. 


Ilornl'lendic  and  micaceous  schists  and  slates,  -with 
beds  and  dikes  of  granite.  Thickness  unknown. 
Found  at  the  bottom  of  the  Grand  Canon. 


44  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

REMARKS   ON   THE   GENERAL  SECTION. 

The  thicknesses  which  I  have  given  in  the  table  are  considered  to  be 
nearly  an  average.  Many  of  the  groups  are  much  thicker  in  some  places, 
and  thinner  in  others.  If  the  maximum  thickness  of  each  had  been  given, 
the  sum  would  have  been  more  than  70,000  feet;  while  if  the  minimum 
had  been  given  the  sum  would  have  been  reduced  nearly  to  50,000  feet. 
The  Mesozoic  and  Paleozoic  sediments  in  all  latitudes  where  they  have 
been  studied,  are  found  to  attenuate  as  you  pass  from  the  western  to  the 
eastern  border  of  the  province. 

In  characterizing  the  rocks  I  have  attempted  to  give  only  those 
features  which  are  general  throughout  the  province  so  far  as  it  has  been 
studied ;  but  there  are  many  local  peculiarities  which  we  have  observed 
and  which  will  appear  in  the  detailed  reports. 

LOCALITIES  WHERE   THE    SEVERAL  GROUPS   CAN   BE   STUDIED. 

I  now  append  a  few  localities  where  these  several  groups  can  be  seen 
under  favorable  circumstances.  They  might  be  multiplied  greatly,  but 
perhaps  no  good  purpose  would  thus  be  served. 

BISHOP   MOUNTAIN   CONGLOMEEATE. 

The  Bishop  Mountain  Conglomerate  can  be  seen  on  the  summit  of 
Bishop  Mountain,  where  it  lies  unconformably  on  the  eroded  beds  of  the 
Bitter  Creek  Group.  A  fine  exposure  can  also  be  seen  on  the  summit  of 
the  Quien  Hornet  Mountain. 


BROWN'S  PARK  GROUP. 


This  group  is  well  represented  at  Brown's  Park,  in  Northeastern  Utah 
and  Northwestern  Colorado. 

A  good  section  can  be  obtained  in  the  high  bluffs  on  the  west  side  of 
the  Snake  River  by  commencing  about  five  miles  above  its  confluence  with 
the  Yampa  where  these  beds  are  seen  to  rest  unconformably  against  Car- 
boniferous strata  at  the  foot  of  the  mountain.  In  going  north  two  minor 
flexures  are  passed  where  the  upper  members  of  the  group  are  exposed ; 
and,  on  reaching  a  third  and  greater  upheaval,  the  group  is  exposed  from 
summit  to  base,  and  is  seen  to  rest  unconformably  upon  Bridger  beds. 


LOCALITIES  WHERE  THE  GROUPS  CAN  BE  STUDIED.  45 

BEIDGER    GROUP. 

This  group  can  be  well  studied  in  the  vicinity  of  Fort  Bridger,  at 
Church  Buttes,  and  in  the  Cameo  Mountains.  It  has  an  extensive 
development  in  this  region,  i.  e.,  west  of  the  Green  River  and  north  of  the 
Uinta  Mountains,  and  is  usually  well  exposed.  An  outlying  patch  can  be 
seen  between  Vermilion  Creek  and  the  Snake  River,  on  the  north  side  of 
the  Dry  Mountains.  It  can  also  be  finely  studied  at  Haystack  Mountain. 

• 

UPPER    GREEN    RIVER    GROUP. 

The  Plant  Beds  of  this  group  are  well  exposed  to  the  north  of  Green 
River  Station,  and  between  that  point  and  Alkali  Stage  Station  in  many 
gulches  and  canons.  They  are  also  well  exposed  in  the  cuts  of  the  Union 
Pacific  Railroad  between  Green  River  Station  and  Bryan.  Another  good 
exposure  can  be  seen  in  the  escarpments  on  either  side  of  Henry's  Fork, 
commencing  about  five  miles  above  its  mouth  and  continuing  up  the  stream 
for  several  miles. 

The  Tower  Sandstone  is  well  shown  in  the  cliffs  at  Green  River 
Station  and  in  that  vicinity,  especially  up  and  down  the  river  for  several 
miles.  This  sandstone  is  also  well  exposed  on  the  eastern  side  of  the  Green 
River,  below  the  mouth  of  Currant  Creek. 

LOWER    GREEN    RIVER    GROUP. 

This  group  is. well  exposed  along  the  Green  River  from  Green  River 
Station  southward  for  ten  miles  where  a  detailed  section  has  been  made 
and  will  be  given  hereafter.  It  is  also  well  exposed  in  many  of  the  escarp- 
ments of  the  Quien  Hornet  Mountain.  We  again  find  it  well  exposed  in 
the  escarpments  a  few  miles  northeast  from  the  head  of  Vermilion  Canon. 
Fine  exposures  are  seen  on  the  Snake  River  six  miles  above  the  northern 
foot  of  Junction  Mountain.  The  elevated  ledges  known  as  Pine  Bluffs,  near 
the  sources  of  the  eastern  tributaries  of  Vermilion  Creek,  are  capped  with 
the  limestones  and  bituminous  shales  of  this  group. 

BITTER    CREEK    GROUP. 

This  group  is  well  exposed  along  Bitter  Creek  in  the  vicinity  of  Bitter 


46  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

Creek  and  Black  Buttes  Stations.  A  fine  section-  can  be  obtained  by  com- 
mencing at  Pine  Bluffs  at  the  foot  of  the  limestone  beds  and  passing  in  a 
direction  a  little  north  of  west  until  the  massive  gray  sandstone  of  the  next 
group  is  reached.  Across  this  stretch  of  country  the  beds  dip  to  the  east, 
and  their  outcropping  edges  stand  in  a  succession  of  ledges  and  can  be  well 
studied.  It  is  better  to  follow  the  line  which  I  have  indicated  than  to  make 
a  section  along  Bitter  Creek,  as  there  is  a  fault  passing  between  old  Hall- 
ville  and  Black  Buttes  Station,  and  it  is  difficult  along  that  line  to  determine 
the  amount  of  the  fault,  and  hence  there  is  a  liability  of  duplicating  or  omit- 
ting some  of  the  lower  members  of  this  section.  This  fault  will  be  explained 
hereafter. 

The  junction  of  the  Bitter  Creek  Group  with  the  Lower  Green  River 
can  be  very  well  seen  in  the  escarpment  at  Pine  Bluffs;  one  hand  can  be 
placed  upon  a  limestone  of  the  upper  group  and  the  other  on  a  massive  bad- 
land  sandstone  of  the  lower.  In  like  manner  the  junction  between  this 
group  and  the  next  lower  can  be  well  seen  in  an  escarpment  east  of  and 
facing  Black  Butte.  There  is  an  escarpment  on  the  northeast  side  of  Bitter 
Creek,  facing  that  stream  and  extending  from  Hallville  Section  House  to 
Point  of  Rocks,  where  the  upper  sandstones  of  the  Point  of  Rocks  Group 
stand  in  an  almost  vertical  cliff,  and  the  lower  members  of  the  Bitter  Creek 
series  can  be  seen  to  rest  upon  this  sandstone  unconformably.  These  beds 
are  exceedingly  friable,  ferruginous  sandstones  and  shales,  and  in  many 
places  a  shelf  or  terrace  is  seen  between  the  foot  of  the  Bitter  Creek  shales 
and  the  brink  of  the  cliffs  formed  of  the  Point  of  Rocks  sandstone. 

This  group  can  be  studied  along  the  Union  Pacific  Railroad  west  of  Rock 
Springs.  Three-fourths  of  a  mile  east  of  Lawrence  Section  House  the  railroad 
passes  with  an  abrupt  curve  around  a  ledge  of  rocks,  where  the  junction  of 
the  Bitter  Creek  series  and  the  Lower  Green  River  can  be  plainly  seen. 
Here  you  may  place  your  forefinger  on  a  limestone  of  the  Lower  Green 
River  and  your  thumb  on  a  bad-land  sandstone  of  the  Bitter  Creek  Group. 
In  the  escarped  hills  on  either  side,  the  line  between  the  limestones  and 
buff  and  pink  sandstones  can  be  plainly  seen.  These  rocks  dip  to  the  west 
at  an  angle  of  about  four  degrees,  and  as  you  go  eastward  this  dip  gradually 
increases,  and  bed  after  bed  of  the  Bitter  Creek  Group  can  be  seen  well  ex- 


LOCALITIES  WHERE  THE  GROUPS  CAN  BE  STUDIED.  47 

posed  by  passing  back  and  forth  among-  the^hills  until  reaching'  a  point  about 
a  mile  and  a  half  west  of  Blair's  coal  mine,  you  come  to  a  high  ridge  or 
hogback  where  the  series  ends.  This  hogback  is  composed  of  the  upper 
sandstone  of  the  Point  of  Rocks  Group;  the  junction  of  the  two  groups  on 
this  line  can  be  very  well  seen.  The  gray  sandstone  of  the  Point  of  Rocks 
Group  is  massive  and  indurated.  The  brown,  ferruginous .  shales  of  the 
Bitter  Creek  Group  yield  readily  to  atmospheric  degradation,  and  have  been 
swept  away  back  of  the  ridge  or  hogback,  leaving  broad,  naked  surfaces  of 
gray  sandstone. 

Another  fine  section  can  be  obtained  by  commencing  on  the  southern 
face  of  the  Quien  Hornet  Mountain  and  passing  over  the  escarped  ledges 
in  a  southwesterly  direction  along  the  bluffs  of  Red  Creek  until  you  reach 
the  foot  of  the  great  hogback  which  is  composed  of  beds  of  the  Point  of 
Rocks  Group. 

Vermilion  Creek  in  its  upper  course  runs  through  beds  of  this  group. 
Its  many  wet-weather  tributaries  have  carved  the  country  with  deep  but 
flaring  channels,  and  the  naked  beds  can  be  seen  on  every  hand;  and  the 
bad-land  hills  are  filled  with  fossils;  but  the  lower  members  of  the  group 
cannot  well  be  studied  by  reason  of  some  complicated  but  interesting  dis- 
placements that  are  observed  a  little  north  of  the  Vermilion  Cafion.  These 
displacements  will  be  discussed  hereafter. 

To  the  southward  this  group  of  rocks  is  developed  over  broad  areas. 
The  Cafion  of  Desolation  for  much  of  its  course  is  cut  through  these  rocks, 
and  in  its  high  walls  this  group  can  be  studied  to  advantage.  The  Pink 
Cliffs  of  Southern  Utah  are  of  this  age. 

POINT    OF    ROCKS    GROUP. 

A  good  section  of  this  group  can  be  obtained  at  Point  of  Rocks  Station. 
There  is  a  series  of  cliffs  and  abruptly  escarped  hills  extending  from  a  point 
northeast  of  the  station  in  a  westerly  direction  for  several  miles.  These 
escarpments  face  Bitter  Creek  and  the  Union  Pacific  Railroad.  In  the  cliff 
immediately  back  of  the  depot  at  Point  of  Rocks  the  junction  between  the 
Bitter  Creek  and  Point  of  Rocks  Groups  is  well  seen.  As  I  have  already 
described,  the  lower  members  of  the  upper  groups  are  brown,  friable,  arena- 


48  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

ceous,  ferruginous  shales,  with  occasional  beds  of*  soft  sandstone,  all  weath- 
ering easily;  and  the  line  of  junction  between  that  and  the  massive  gray 
sandstone  which  forms  the  summit  of  the  Point  of  Rocks  Group  can  be 
plainly  seen.  In  these  shales  immediately  overlying  the  massive  sandstone 
there  are  beds  and  seams  of  coal.  The  first  massive  sandstone  is  the  Upper 
Hogback  Sandstone.  These  rocks  all  have  an  easterly  dip,  and  as  you  go 
westward  you  soon  reach  the  base  of  the  Upper  Hogback  Sandstone,  then 
pass  the  beds  of  irregularly  bedded  shales  and  sandstones  until  you  reach  a 
second  massive,  gray  sandstone,  which  in  many  places  is  broken  into  two 
or  more  beds.  This  is  the  Middle  Hogback  Sandstone.  Still  going  west- 
ward, massive  and  thinly  bedded  sandstones  of  yellowish-buff  color  alter- 
nating with  massive  beds  of  light  gray  or  white  sandstone,  are  seen.  About 
six  miles  from  the  station  -the  railroad  turns  southward  and  debouches 
from  the  narrow  canon  valley  of*  the  Point  of  Eocks  into  the  broad  open 
valley  of  the  Salt  Wells.  To  reach  the  base  of  the  Point  of  Rocks  Group 
it  is  necessary  to  diverge  from  the  railroad,  which  passes  along  the  foot  of 
the  cliffs,  and  eontinue  in  a  westerly  direction  until  the  last  massive  gray 
sandstone  is  reached.  It  will  then  be  noticed  that  the  massive  beds,  both 
yellow  and  gray,  have  been  passed,  and  that  another  series  of  more  thinly 
laminated  beds  underlie  the  massive  series.  These  alternating  beds  of  gray 
and  buff  belong  to  the  Golden  Wall  Group.  The  separation  between  these 
two  groups  at  this  point  is  not  as  plainly  marked  as  at  many  other  regions. 
The  whole  thickness  at  this  locality  is  about  1,800  feet. 

When  Messrs.  Meek  and  Bannister  made  their  section  along  this  line, 
or  their  Point  of  Rocks  Section,  they  commenced  a  few  hundred  feet  below 
the  summit  of  the  group  and  ended  about  300  feet  above  its  base,  which 
was  not  seen  by  them;  for  in  turning  southward  with  the  railroad  they 
crossed  two  great  faults  having  their  throw  to  the  north.  The  lines  of  fault- 
ing pass  along  a  valley  showing  no  rock  exposures,  and  when  they  passed 
out  into  Salt  Wells  Valley  they  were  on  beds  of  the  Salt  Wells  Group  at  a 
horizon  of  six  or  eight  hundred  feet  below  the  summit. 

Another  good  section  of  this  group  can  be  obtained  at  Rock  Springs. 
A  few  hundred  yards  west  of  the  mineral  spring  known  as  Rock  Spring,  a 
great,  massive  sandstone  stands  in  a  ledge,  the  beds  dipping  to  the  west  at 


LOCALITIES  WHERE  THE  GROUPS  CAN  BE  STUDIED.  49 

an  angle  of  about  1C  degrees.  The  brown  shales  and  sandstones  of  the 
upper  group  have  been  stripped  from  this  sandstone  over  broad  areas,  and 
the  junction  between  the  two  can  be  plainly  seen.  Starting  from  this  point 
and  going  eastward,  a  series  of  gray  sandstones  above,  interrupted  by  car- 
bonaceous shales  and  beds  of  coal,  are  passed;  then  gray  and  buff  sand- 
stones are  seen  until  the  Van  Dyke  Mine  is  reached.  A  little  east  of  this 
point  we  come  to  the  base  of  the  Point  of  Rocks  Group,  and  reach  the 
summit  of  the  Salt  Wells  Group.  I  have  never  examined  this  point  with 
sufficient  care  to  enable  me  to  indicate  the  exact  junction,  but  as  described 
in  the  Point  of  Rocks  Section  above,  the  junction  is  not  very  well  denned. 

Fine  sections  can  be  obtained  on  either  side  of  the  Green  River  two 
miles  above  Flaming  Gorge  where  this  group  of  beds  was  measured  and 
found  to  be  2,000  feet  in  thickness.  Here  they  stand  on  edge,  and  their 
stratification  can  be  well  seen. 

The  foot  of  Desolation  Canon,  and  Gray  Canon  on  the  Green  River 
affords  another  fine  section,  and  the  group  can  be  well  studied  in  the  Wa- 
satch  Cliffs  at  the  head  of  the  Escalante  River,  and  in  the  hills  at  the  foot 
of  the  Pink  Cliffs,  in  Southern  Utah. 

SALT    WELLS    GROUP. 

Standing  south  of  the  debouchure  of  the  Point  of  Rocks  Canon  into 
Salt  Wells  Basin,  and  looking  eastward,  lines  of  cliffs  and  escarped  hills  are 
seen.  Climbing  these  hills  until  the  first  massive,  light  gray  sandstone  is 
found,  you  reach  the  summit  of  the  Salt  Wells  Group  and  the  base  of  the 
Point  of  Rocks.  Then,  turning  westward  you  descend  from  this  eminence, 
and  still  continuing  in  a  westerly  direction  you  pass  along  the  foot  of  an 
escarpment  which  faces  the  railroad,  the  beds  of  which  dip  at  an  angle  of 
about  8  degrees  to  the  east,  and  hence  you  are  passing  from  higher  to  lower 
strata.  Still  continuing1  in  this  direction  for  several  miles,  and  crossing-  the 

O  7  O 

broad  valley  of  Pretty  Creek,  you  reach  at  last  the  axis  of  the  upheaval 
near  Baxter  Section  House.  Here  we  find  an  escarpment  facing  the 
north,  the  rocks  of  which  are  light  colored,  arenaceous  shales  above  and 
dark,  argillaceous  shales  below.  The  arenaceous  shales  are  at  the  base  of 
the  Salt  Wells  Group;  the  black  shales  below  are  believed  to  belong  to  the 
4  P  a 


50  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

summit  of  the  next  group.  No  examination  of  the  section  has  been  made 
along  this  line  nor  have  the  beds  been  studied  in  detail,  but  the  upper  and 
lower  limits  of  the  gfoup  are  tolerably  well  defined.  On  the  Green  River, 
about  two  miles  and  a  half  above  Flaming  Gorge,  the  junction  between  the 
black  shales  of  the  lower  group  and  the  yellow  shales  of  the  upper  can  be 
well  seen,  and  the  junction  between  this  group  and  the  Point  of  Rocks 
Group  is  also  well  seen.  Here  the  beds  stand  on  edge  and  were  measured, 
and  a  thickness  of  nearly  2,000  feet  obtained.  This  group  can  be  well 
studied  in  narrow  zones  along  the  northern  flanks  of  the  Uinta  Mountains. 
Fine  exposures  occur  in  the  Pink  Cliffs  and  at  Gunnison's  Butte  on  the 
Green  River  south  of  Gray  Canon,  and  north  of  the  point  where  that  river 
was  crossed  by  Captain  Gunnison  on  his  trip  to  Utah  in  1853. 

SULPHUR  CREEK  GROUP. 

This  group  of  black  shales  can  be  well  seen  in  the  hills  near  Hilliard 
Station  on  the  Union  Pacific  Railroad.  Here  Sulphur  Creek  cuts  through 
them  for  several  miles.  In  Professor  Meek's  "Section  on  Sulphur  Creek 
near  Bear  River,"  his  "No.  1"  is  the  summit  of  the  group.  The  locality 
does  not  present  a  good  type  from  the  fact  of  the  great  displacements  to 
which  the  beds  have  been  subjected.  Their  relation  to  underlying  beds  can- 
not be  determined  with  certainty;  but  on  the  north  and  south  sides  of  the 
Uinta  Mountains  many  fine  exposures  are  found.  I  have  already  mentioned 
the  point  where  the  junction  of  this  group  ,with  the  overlying  can  be  seen, 
north  of  Flaming  Gorge;  the  beds  dip  to  the  north  at  an  angle  of  nearly 
90  degrees,  and  on  the  south  side  of  Henry's  Fork  the  junction  of  the  black 
shales  with  the  next  group  is  plainly  seen.  Here  the  beds  were  measured 
and  found  to  be  2,050  feet  in  thickness.  . 

Farther  eastward  between  the  head  of  Dry  Lake  Valley  and  Vermilion 
Creek  the  beds  dip  to  the  north  at  an  angle  of  about  25  degrees  and  are 
truncated  with  the  great  Uinta  flexure.  Still  farther  south  in  the  Escalante 
Valley,  Paria  Valley,  Kanab  Valley  and  many  other  localities,  the  entire 

group  is  well  exposed. 

HENRY'S  FORK  GROUP. 

This  group  can  be  well  studied  at  the  typical  locality  which  is  on  the 


LOCALITIES  WHERE  THE  GROUPS  CAN  BE  STUDIED.  51 

south  side  of  Henry's  Fork,  commencing  about  two  miles  above  its  mouth 
and  extending  for  many  miles  to  the  westward.  These  beds  stand  on  edge 
and  are  well  exposed.  Their  junction  with  the  black  shales  can  be  plainly 
seen  and  the  base  of  the  group  is  the  second  conglomerate  below  the  teliost 
shales;  the  teliost  shales  themselves  constitute  a  conspicuous  datum  point 
from  which  to  study  the  stratigraphy  of  this  district.  Many  sections  can  be 
obtained  on  either  side  of  the  Uinta  Mountains.  Perhaps  no  better  place 
can  be  found  than  on  Ashley's  Creek,  where  the  group  stands  in  a  hogback 
near  Dodd's  Ranch.  Many  other  localities  could  be  mentioned  on  the 
Price,  Escalante,  Dirty  Devil,  Paria  and  Kanab  Rivers. 

FLAMING    GORGE    GROUP. 

This  group  can  be  well  studied  at  the  typical  locality,  viz,  in  the  vicin- 
ity of  Flaming  Gorge.  Commencing  at  the  conglomerate  above  mentioned 
as  forming  the  base  of  the  Henry's  Fork  Group,  you  pass  southward  over 
the  upturned  edges  of  the  beds,  crossing  the  bad-land  sandstones,  then  the 
Mid-group  Limestones,  then  the  bad-land  indurated  sandstones,  until  the 
White  Cliff  Limestone  is  reached.  The  massive,  cross-bedded  sandstones 
beneath,  is  a  very  conspicuous  feature  of  the  landscape,  and  forms  the  sum- 
mit of  the  next  group. 

In  mentioning  the  typical  and  other  localities  of  the  foregoing  groups 
I  have  not  given  detailed  sections,  as  in  a  following  chapter,  on  the  descrip- 
tive geology  of  the  Uinta  Mountains  and  adjacent  country,  it  will  be  neces- 
sary to  describe  more  minutely  the  stratigraphy  of  all  these  groups.  These 
typical  localities  excepting  that  of  the  Sulphur  Creek  Group  all  fall  within 
the  area  that  is  to  be  described.  The  typical  localities  of  the  remaining  or 
lower  groups  are  without  the  region  described  in  this  volume,  and  hence  I 
shall  give  sections  of  the  groups  as  they  occur  at  the  typical  localities. 

WHITE    CLIFF    GROUP. 

The  locality  selected  as  representing  the  typical  series  of  this  group  is 
in  Southern  Utah.  Here  a  long  irregular  escarpment  or  line  of  cliffs  is  seen 
facing  southward,  from  which  the  geologist  may  overlook  two  other  sub- 
parallel  lines  of  cliffs  and  see  in  the  distance  the  walls  of  the  Grand  Canon 


52  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

of  the  Colorado.  The  Paria,  Kanab  and  Rio  Virgen,  with  their  many  tribu- 
taries that  head  in  the  Pink  Cliffs  above  and  to  the  north,  have  cut  many 
canons  and  canon  valleys  through  these  escarpments,  and  here  the  structural 
geology  and  stratigraphy  are  plainly  revealed;  not  only  of  the  White  Cliff 
Group  but  also  of  the  Vermilion  Cliff  and  Shinarump  Groups.  The  sec- 
tion which  I  shall  give  of  these  three  groups  was  made  along  the  course 
of  the  Kanab  in  the  winter  of  1871. 

The  escarpment  known  as  the  White  Cliffs  presents  to  the  mid-day  sun 
a  bold  wall  of  pure  white  or  golden  sandstone  reflecting  its  rays  with  a  shim- 
mering, brilliant  light.  At  such  a  time  the  traveler  toiling  over  the  and  sand- 
dunes  below,  sees  before  him  to  the  east  or  west  a  long  stretch  of  pink  and 
vermilion  hills — hills  of  shifting  sands,  with  no  promise  of  spring  or  brook 
at  which  his  thirst  may  be  quenched;  the  precipice  of  the  Vermilion  Cliffs 
to  the  south,  and  the  White  Cliffs  a  wall  of  fire  to  the  north.  A  more  con- 
spicuous or  well  denned  topographic  feature  could  not  well  be  imagined. 

On  top  of  the  wall  and  usually  a  little  back  from  the  edge  the  lime- 
stones which  form  the  base  of  the  Flaming  Gorge  Group  is  seen.  This  lime- 
stone has  been  traced  from  point  to  point  along  the  intermediate  country 
for  the  entire  distance  from  Flaming  Gorge  to  the  White  Cliffs. 

The  following  is  a  section  of  the  White  Cliff,  Vermilion  Cliff,  and  Shina- 
rump Groups'  from  the  base  of  these  limestones  to  the  summit  of  the  Upper 
Aubrey  Group. 


LOCALITIES  WHERE  THE  GROUPS  CAN  BE  STUDIED.  53 


FIG.    9.— SECTION    OF    WHITE     CLIFF,     VERMILION    CLIFF, 
AND  SHINARUMP  GROUPS. 


1,000 


2,000 


3,000 


4,000 


WHITE    CLIFF    GROUP. 

No.  1,  600  feet.    Light  gray  or  white  sandstone  ;  massive  ;  cross-bedded. 

No.  2,  300  feet.    Bright  pink  and  vermilion  sandstone  ;  cross-bedded. 

No.  3,  200  feet.    Gray,  red,  and  brown  sandstone ;  cross-bedded ;  of  many  cojors  ;  tl 

colors  appearing  in  bands  with  oblique  lamination,  giving  the  rocks  a  beautifully  v 

riegated  appearance. 


the 
•a- 


VERMILION    CLIFF    GROUP. 

No.  4,  50  foot.    Red  friable  sandstone. 

No.  5,  180  foot.    Massive  sandstone ;  cross-bedded ;  with  a  few  irregular  beds  of  lime- 

stoiie  not  persistent  horizontally;  stained  rod  on  exposed  surfaces. 
No.  C,  320  feet.    Red  sandstone  ;  thickly  bedded. 
No.  7,  2  feet.    Calciferous  sandstone. 
No.  8,  100  feet.    Orange  or /vermilion  sandstone. 
No.  9,  5  feet.    Light  gray  sandstones. 
No.  10,  400  feet.    Orange  sandstones  ;  rather  massively  bedded. 


SHINARUMP    GROUP. 

No.  11,  800  feet.     Bad-land  sandstones,  rapidly  disintegrating  ;  argillaceous ;   weather 

ing  in  variegated  hills. 
No.  12,  80  feet.    Conglomerate. 

No.  13,  193  feet.    Red,  bail-land  sandstone  ;  very  friable,  with  much  gypsum. 
No.  14,  100  feet.    Greenish  gray  bad-land  sandstone,  with  much-  gypsum,  and  rapidly 

disintegrating. 

No.  15,  8  feet.    Compact  gray  sandstone. 

No.  16,  3!  0  foot.    lied  sandstones  and  arenaceous  shales  ;  gypsum  in  seams  and  joints. 
No.  17,  250  feet.    Red  and  brown  sandstone ;  rather  thinly  bedded,  with  many  ripple 

marks. 
No.  18,  50  foot.    Conglomerate  with  angular  and  rounded  fragments  of  limestone  in  a 

matrix  of  calciferous  sand. 


The  sandstones  of  this  group  are  well  seen  in  the  vicinity  of  Flaming 
Gorge  on  the  south  side  of  the  Green  River;  again  between  Dry  Lake  and 
Vermilion  Creek  north  of  Po  Canon,  and  in  a  narrow  zone  on  the  south  side 
of  the  Uinta  Mountains,  and  in  many  other  places  on  the  tributaries  of  the 
Green  and  Colorado  Rivers;  and  everywhere  the  lithologic  characteristics 
are  more  or  less  persistent.  The  cross-bedded  sandstones  usually  form  a 
conspicuous  landmark. 


54  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

VERMILION    CLIFF    GROUP. 

The  wagon  road  from  Toquerville  to  Paria,  a  little  town  on  the  Paria 
River,  soon  after  climbing1  the  Hurricane  Ledge  reaches  the  foot  of  the 
Vermilion  Cliffs,  and  continues  at  this  geological  horizon  until  it  commences 
to  descend  into  the  valley  of  the  Paria.  For  seventy-five  miles  the  road 
lies  under  this  great  ledge,  whose  salient  buttes,  deep  alcoves,  terraced  and 
buttressed  walls,  towering  pinnacles,  all  brightly  colored  in  orange,  vermilion 
and  purple,  and  dotted  here  and  there  with  straggling  cedars  and  nut  pines, 
constitute  a  grand  panorama  to  the  passing  traveler. 

Flaming  Gorge  on  the  Green  River  is  cut  through  beds  of  this  group 
and  receives  its  name  from  the  bright  colors  of  vermilion  sandstone  ;  Laby- 
rinth Cailon  is  cut  through  vermilion  sandstone  ;  Glen  Canon  for  the  greater 
part  of  its  course  also,  and  fine  exposures  are  seen  along  the  Colorado 
Chiquito. 

SHINARUMP    GROUP. 

South  of  the  Vermilion  Cliffs  a  low  ledge  or  escarpment  is  seen  capped 
with  conglomerate.  This  is  the  Shinarump  Conglomerate. 

The  variegated  beds  above  and  below  the  conglomerate  are  seen  in 
many  places  on  either  flank  of  the  Uinta  Mountains,  and  from  time  to  time 
this  horizon  is  brought  up  by  faults  or  flexures  in  all  the  stretch  of  country 
which  intervenes  between  the  Shinarump  Cliffs  and  the  Uinta  Mountains. 

UPPER    AUBREY    GROUP. 

Mr.  Gilbert,  as  geologist  of  the  Wheeler  expedition,  described  certain 
groups  of  limestones,  sandstones  and  shales  as  the  Aubrey  Group.  Previous 
to  his  publication  I  had  in  manuscript  divided  these  beds  into  two  groups 
and  given  them  names ;  but  in  carrying  out  my  determination  to  use  the 
names  of  groups  which  had  been  adopted  by  others  so  far  as  such  names 
were  available,  I  have  decided  to  call  the  two  groups  into  which  I  wish  to 
divide  the  Aubrey  beds  of  Mr.  Gilbert,  the  Upper  and  Lower  Aubrey 
Groups. 

The  beds  of  the  Upper  Aubrey  are  exposed  for  thousands  of  miles 
along  the  Grand  Canon  of  the  Colorado  and  its  lateral  canons,  everywhere 


LOCALITIES  WHEEE  THE  GROUPS  CAN  BE  STUDIED.  55 

forming  the  summit  of  the  walls  of  these  gorges.  They  are  also  well  exposed 
along  Marble  Canon ;  and  Cataract  Canon  at  the  junction  of  the  Grand  and 
Green  furnishes  another  good  section.  Good  sections  are  obtained  at  Horse- 
shoe Canon,  the  Canon  of  Lodore,  Whirlpool  Canon,  and  Split  Mountain 
Canon  in  the  Uinta  Mountains.  Its  junction  with  the  Shinarump  Group 
above,  in  all  these  places  can  be  plainly  seen,  and  in  like  manner  its  junction 
with  the  Lower  Aubrey  Group  is  apparent.  To  the  southward  in  the  Grand 
Canon  country  these  beds  are  a  series  of  cherty  limestones.  At  the  junction 
of  the  Grand  and  Green  they  are  a  series  of  sandstones  with  intercolated 
cherty  limestones,  with  a  homogeneous  sandstone  at  the  summit  150  feet 
in  thickness.  In  the  Uinta  Mountains  we  have  a  homogeneous  gray  Sand- 
stone which  we  call  the  Yampa  Sandstone,  from  1,000  to  1,200  feet  in  thick- 
ness, capped  by  a  bed  which  is  believed  to  be  the  equivalent  of  the  one 
mentioned  as  found  at  the  summit  of  the  series  at  the  junction  of  the  Grand 
and  Green,  and  varies  from  150  to  200  feet  in  thickness.  On  the  south  side 
of  the  Uinta  Mountains  it  is  an  indurated,  calciferous  sandstone,  but  on  the 
north  side  of  the  mountains  it  is  a  cherty  limestone,  and  on  both  flanks  of 
these  mountains  it  is  characterized  by  a  species  of  bellerophon.  Here  we 
have  called  it  the  Bellerophon  Limestone. 


LOWER    AUBREY    GROUP. 


The  Lower  Aubrey  Group  is  seen  underlying  the  Upper  Aubrey  at 
all  the  localities  mentioned  for  that  group.  In  the  Grand  Cation  it  is  a 
conspicuous  group,  its  relations  to  the  Upper  Aubrey  and  the  Red  Wall 
Groups  being  well  marked.  At  the  junction  of  the  Grand  and  Green  the 
lines  of  demarkation  cannot  be  so  closely  drawn  but  they  appear  again 
very  clearly  in  the  Uinta  Mountains. 

RED    WALL    GROUP. 

The  Red  Wall  Group  is  the  most  conspicuous  feature  of  the  Grand 
Canon  of  the  Colorado  and  its  tributary  gorges.  It  often  stands  in  a  vertical 
wall  2,000  feet  high  or  more,  and  is  everywhere  carved  into  a  series  of 
grand  amphitheaters,  which  I  have  elsewhere  tried  to  describe.  There  are 
two  well  defined  members  in  the  Grand  Canon  country ;  the  upper  one 


5(5  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

thousand  feet  is  a  massive,  homogeneous,  saccharoid  limestone  ;  the  lower 
one  thousand  feet  is  composed  chiefly  of  thin  beds  of  indurated  limestones 
of  very  irregular  stratification  surfaces.  These  beds  are  somewhat  argilla- 
ceous. The  group  is  not  well  exposed  in  Cataract  Caiion,  as  the  river  has  not 
yet  cut  through  the  beds  at  that  point,  and  some  very  curious  displacements 
along  the  river  serve  to  obscure  the  characteristics  of  the  beds  that  are 
exposed.  In  the  Uinta  Mountains  the  two  members  seen  in  the  Grand 
Canon  are  represented  by  two  massive,  indurated  limestones,  often  con- 
taining chert  and  separated  by  arenaceous  shales. 

TON  TO    GKOUP. 

I  have  elsewhere  called  these  the  rust  colored  beds,  but  Mr.  Gilbert 
has  called  them  the  Tonto  Group,  and  I  accept  his  name.  These  beds  are 
seen  to  overlie  unconformably  the  beds  of  the  Grand  Canon  Group  and  of 
the  Grand  Caiion  Schists.  They  are  seen  well  exposed  along  or  near  the 
bottom  of  the  Grand  Canon,  where  the  river  makes  its  double  detour 
around  tlie  Kaibab  Plateau,  and  again  farther  westward,  where  the  river 
makes  another  detour  around  the  Shi-wits  Plateau. 

A  group  of  sandstones  and  arenaceous  shales  is  found  below  the  Red 
Wall  horizon  in  Lodore  and  Whirlpool  Canons,  where-  the  Green  River 
cuts  through  the  Uinta  Mountains.  In  the  beds  of  this  latter  place  I  have 
discovered  Carboniferous  fossils,  and  suppose  them  to  be  of  the  same  age  as 
the  Tonto  Group ;  yet,  as  Mr.  Gilbert  has  considered  the  Tonto  beds  to  be 
of  Silurian  Age,  I  have  called  the  latter  Lodore  Group  provisionally. 
From  geological  considerations,  I  am  inclined  to  consider  the  Tonto  Group 
as  forming  the  base  of  the  Carboniferous  series.  The  supposed  Cnmami 
and  metamorphosed  corals  discovered  by  Mr.  Gilbert  are  not  deemed  by  me 
to  furnish  sufficient  evidence  of  their  greater  age.  Their  geological  rela- 
tions being  apparently  the  same  as  the  Lodore  series,  I  am  inclined  to 
refer  them  to  the  same  horizon  ;  the  latter  have  been  demonstrated  to 
be  Carboniferous.  •  My  opinion  is  strengthened  by  the  fact  that  I  find  in 
the  Grand  Canon  10,000  feet  of  sandstones,  shales  and  limestones,  under- 
lying them  unconformably,  and  hence  separated  by  a  long  period  of  ero- 
sion, and  'at  the  base  of  this  latter  series  I  have  found  Silurian  fossils.  I 


TTY 


TJinta  Mountains. 


FIG.  10. — Comparative  sections  of  Carboniferous  strata. 
Cataract  Canon. 


Grand  Canon. 


-     1000 


_     2000 


3000 


-      4000 


UINTA  MOUNTAIN  SECTION.  57 

consider  the  Tonto,  Red  Wall,  Lower  Aubrey,  and  Upper  Aubrey  Groups 
to  represent  the  Carboniferous  time  from  base  to  summit. 

In  Figure  10  I  give  a  Uinta  Mountain,  Cataract  Canon,  and  Grand 
Caf5  on  section  of  these  groups,  side  by  side,  for  comparison.  The  Uinta 
Mountain  and  Cataract  Canon  Sections  were  made  by  Mr.  J.  F.  Steward. 

UINTA   MOUNTAIN    SECTION. 

By  J.  F.  STEWARD. 
UPPER   AUBREY    GROUP. 

No.   1,   175  feet.   Calciferous    sandstone,  containing  Bdlerophon,  con- 

chifers,  &c. 

No.  2,  1,400  feet.  Massive  buff  sandstone. 

LOWER   AUBREY    GROUP. 

No.  3,  90  feet.  Limestone,  mottled  dark,  drab,  and  buff;  very  hard; 
cup  corals  and  Product  us  abundant. 

No.  4,  200  feet.  Buff  limestone,  very  fossiliferous ;  Spirtfer,  Atliyris,  &c., 
abundant. 

No.  5,  75  feet.  Heavy  bedded,  bluish-drab  limestone ;  lower  portion 
buff  colored.  This  bed  is  filled  with  nodules  of  chert,  (red,  pink  and  purple 
chalcedony;)  also  abounds  in  remains  of  cyathophylloid  corals,  Spinfer, 
and  Productus,  all  siliceous. 

No.  6,  90  feet.  Thinly  bedded  rocks,  often  shaly ;  texture  variable ; 
composition  calcareous,  arenaceous,  and  argillaceous. 

No.  7,  180  feet.  Compact  buff  sandstone ;  very-hard. 

No.  8,  20  feet.  Dark  bluish-drab  limestone ;  very  hard. 

No.  9,  150  feet,  Light  pinkish-buff,  fine  grained  sandstone. 

RED    WALL    GROUP. 

No.  10,  750  feet.  Heavy  bedded  limestone,  of  pinkish-drab  color,  be- 
coming arenaceous  toward  the  top,  and  of  a  bright  red  color. , 

No.  11,  150  feet.  Reddish,  compact,  and  shaly  sandstones. 

No.  12,  185  feet,  Pinkish,  purple,  brown,  and  bluish  limestone,  colored 
pink  on  the  surface  by  oxide  of  iron  from  the  overlying  sandstone. 


58      SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

No.  13,  750  feet.  Very  compact,  bluish-drab  limestone,  containing 
numerous  seams  of  chalcedony. 

No.  14,  150  feet.  Purplish  and  drab  argillaceous  shales. 

No.  15,  225  feet.  Buff  limestone,  not  well  exposed. 

No.  16,  300  feet.  Limestone  and  sandstone,  thinly  bedded ;  only  upper 
members  exposed. 

LODOKK  GKOUP. 

No.  17.  465  feet.  Thinly  bedded  sandstones,  lying  unconformably  on 

the  Uinta  Group. 

CATARACT   CANON   SECTION. 

By  J.  F.  STEWARD. 
UPPEE    AUBREY    GEOUP. 

No.  1,  150  feet.  Friable,  buff  colored,  homogeneous  sandstone. 

No.  2,  450  feet.  Red  sandstone,  thickly  and  thinly  bedded. 

No.  3,  105  feet.  Fine  grained  sandstone,  ending  in  a  foot  of  very 
brown,  shaly  sandstone. 

No.  4,  95  feet.  Brownish-buff  sandstone. 

No.  5,  25  feet.  Compact,  bluish-drab  limestone,  containing  Productus 
nebrascensiSj  Aihyris  subtilita,  crinoidal  stems,  nodules  of  red  chert,  &c. 

No.  6,210  feet.  Mostly  massively  bedded,  coarse  sandstone,  almost  a 
conglomerate  at  top,  but  gradually  becoming  fine  textured ;  dark  red  and 
shaly  at  base ;  Belleroplion. 

No.  7,  4  feet.  Hard,  compact,  dark  blue  limestone. 

No.  8,  6  feet.  Fine  buff  sandstone. 

No.  9,  50  feet.  Blue  limestone,  divided  into  three  parts  by  arenaceous 
members. 

No.  10,  92  feet.  Drab  sandstone,  very  coarse  at  top,  but  becoming  fine 
at  base. 

LOWEE   AUBEEY    GEOUP. 

No.  11,  721  feet.  Sandstone  and  limestone  in  alternation. 
«,  70  feet.  Drab,  compact  limestone,  containing  in  great  numbers  Allo- 
risma,  Myalina,  &c. ;  also  a  large  Pleurotomaria. 

b,  12  feet.  Fine  grained,  light  gray  sandstone,  very  friable. 

c,  3  feet.  Compact  limestone,  same  as  a. 


CATARACT  CAtfON  8ECTION.  59 

d,  50  feet.  Fine  grained,  incoherent,  ochre-brown  sandstone. 

e,  43  feet.  Light  colored,  arenaceous  shale. 

ft  10  feet.  Dark  gray  limestone,  very  compact  and  hard,  containing 
crinoids. 

<7,  40  feet.  Soft,  friable,  drab  sandstone. 

hj  30  feet.  Compact,  drab,  fossiliferous  limestone. 

ij  75  feet.  Fine  grained,  heavily  bedded,  friable,  lavender-buff  sand- 
stone. 

.;,  12  feet.  Drab,  argillaceous,  arenaceous  shales,  containing  vermiform 
concretions  of  chalcedony. 

&,  18  feet.  Friable  limestone,  largely  composed  of  crinoid  stems,  &c. 

I,  10  feet.  Buff  and  lavender,  fine  grained,  incoherent  sandstone. 

m,  15  feet.  Very  low,  compact,  drab  limestone,  heavily  bedded,  and 
filled  with  fragmentary  fossils. 

n,  12  feet,  Marly,  buff,  crinoidal  sandstone ;  Productus,  Spwifer,  &c. 

o,  42  feet.  Fine  grained  sandstone,  buff  to  drab  at  top,  brown  at  base. 

p,  6  feet.  Dark  gray  limestone,  containing  Productus,  Spirifer,  Chae- 
tetes,  &c. 

q,  40  feet.  Fine,  light  brown  sandstone,  massively  bedded,  changing 
to  shale  at  base. 

r,  25  feet.  Very  hard,  compact,  blue  limestone. 

5,  4  feet.  Blue,  argillaceous  shales,  containing  a  branching  Cfatetes, 
Productus,  &c. 

t,  2  feet.  Hard,  buff  limestone. 

%  60  feet.  Friable,  fine  grained,  buff  sandstone. 

v,  22  feet.  Hard,  bluish  drab  limestone,  with  concretions  of  red  chal- 
cedony. 

w,  75  feet.  Light  buff  sandstone,  very  fine  and  incoherent ;  in  part 
calciferous. 

aj,  50  feet  Hard,  concretionary  limestone,  with  nodules  and  thin  seams 
of  chalcedony. 

y,  15  feet.  Fine  buff  sandstone. 

#,  50  feet.  Very  hard,  dark  drab  limestone,  containing  siliceous  con- 
cretions. 


60  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

RED    WALL    GROUP. 

No.  12.  Thickness  not  determined.  Buffish-lavender,  friable,  fine 
grained  sandstone ;  base  not  seen. 

GRAND   CANON   SECTION. 
UPPER   AUBREY    GROUP. 

No.  1,  145  feet.  Limestone  and  sandstone,  not  very  thickly  bedded. 

No.  2,  220  feet.  Massive  limestone,  brecciated  and  cherty,  and.weather- 
ing  in  columnar  forms. 

No.  3, 170  feet.  Gypsum  and  gypsiferous  sandstone,  irregularly  bedded, 
contorted  and  broken,  stained  brown  in  patches. 

No.  4,  240  feet.  Massive  limestone. 

LOWER   AUBREY    GROUP. 

No.  5.  Bright  red  sandstones,  thinly  and  thickly  bedded,  very  red, 
weathering  in  long  slopes. 

No.  6,  600  feet.  Red  and  buff  sandstones,  heavily  bedded,  exhibiting 
composite  structure,  (cross  bedding,)  with  irregular  and  inconstant  beds  of 
limestone. 

RED    WALL    GROUP. 

No.  7.  Limestones  and  calciferous  sandstones ;  heavily  bedded ;  gray 
and  brown ;  much  chert  in  limestone ;  chert  red  and  vitreous ;  sandstone 
friable. 

No.  8,  800  feet.  Massive  granular  limestone ;  in  some  places  cherty ; 
sometimes  running  horizontally  into  thinly  bedded  rocks. 

No  9,  a,  10  feet.  Friable,  greenish  sandstones,  b,  6  feet.  Purple  sand- 
stones, thinning  out  in  places;  has  the  appearance  of  having  been  eroded. 

No.  10,  300  feet.  Thinly  bedded  limestone,  with  layers  and  nodules  of 
chert. 

No.  11,  50  feet.  Sandstones;  gray  and  buff;  sometimes  mottled; 
probably  calciferous. 

No.  12,  100  feet.  Heavily  bedded  limestone,  with  calciferous  sand- 
stones at  summit. 


GRAND  CANON  SECTION.  61 

No.  1  3,  400  feet.  Thinly  bedded,  bluish  limestone,  with  intercalated, 
thinly  bedded  sandstones  and  clay  shales  below.  The  limestones  are  con- 
cretionary and  brecciated,  and  have  many  cavities  filled  with  calcspar. 

No.  14,  100  feet.  Greenish,  micaceous  shales,  with  beds  of  gray  and 
brown  sandstone,  containing  iron  concretions. 

TONTO    GEOUP. 

No.  15,  75  feet.  Limestones;  a  good  marble;  often  mottled;  some- 
times containing  concretions  of  chert. 

No.  1G,  GOO  feet.  Rust  colored  sandstones  ;  thinly  bedded  ;  indurated; 
reenish  above. 

No.  17,  100  feet.  Brown  sandstone. 


*  *  * 


UINTA    GEOUP. 

The  Uinta  Mountains  are  chiefly  composed  of  Uinta  Sandstone.  The 
western  end  of  this  range  where  it  abuts  against  the  Wasatch  Ranor-e,  I 

o  O  O     / 

have  not  carefully  studied;  but  to  the  eastward  the  broad,  massive  range  is 
a  grand  sandstone  structure.  Other  groups  are  turned  up  on  their  flanks, 
and  in  Red  Creek  Caiion  a  lower  group  is  seen.  On  the  southeast  margin 
of  the  range  a  line  of  peaks  may  be  seen  extending  across  the  Canon  of 
Lodore,  composed  of  groups  of  Red  Wall  Limestone. 

In  the  many  deep  canons  and  gulches  by  which  the  range  is  cleft,  in 
the  many  amphitheaters  that  are  found  along  the  crest  of  the  range,  and  in 
the  mural  faces  of  its  lofty  peaks,  everywhere  the  sandstones  are  made  bare 
to  the  eye  of  the  geologist;  but  the  best  sections  can  be  made  along  the 
canons.  In  a  subsequent  chapter  some  of  these  sections  will  be  given. 

GEAND  CANON  GEOUP. 

This  group  is  exposed  in  the  great  southern  bends  of  the  Grand  Canon, 
where  the  Colorado  River  passes  the  end  of  the  Kaibab  Plateau.  The  best 

* 

exposure  can  be  seen  about  ten  miles  below  the  mouth  of  the  Little  Colo- 
rado. Many  of  the  lateral  streams  coming  in  from  the  west  and  north  cut 
through  this  group  and  afford  fine  exposures.  The  best  one  probably  is  in 


62  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

Kwa-gunt  Valley.     Some  of  the  members  are  again  exposed  at  the  bottom 
of  the  Grand  Canon,  where  it  passes  the  Shi-wits  Plateau. 

Lower  Silurian  fossils  have  been  found  at  the  base  of  this  group. 

EED  CEEEK  GEOUP. 

The  Red  Creek  Quartzite,  with  its  intercolated  beds  of  hornblendic, 
micaceous  and  chloritic  schists,  is  well  seen  in  Red  Creek  Canon.  Other  ex- 
posures can  be  seen  at  the  head  of  Willow  Creek,  a  little  stream  that 
comes  down  from  the  O-wi-yu-kuts  Plateau,  and  empties  into  the  Green 
River  midway  in  Brown's  Park. 

GEAND    CANON    SCHISTS. 

This  group  is  revealed  in  the  depths  of  the  Grand  Canon  in  all  its 
great  southern  bends. 

EPOCHS  SEPARATING  THE  GROUPS. 

BISHOP    MOUNTAIN    CONGLOMEEATE. 

The  Bishop  Mountain  Conglomerate  is  found  at  different  places  to  lie 
unconformably  upon  every  group  of  the  table  which  is  represented  in  the 
Uinta  Mountains  and  adjacent  country.  Its  plane  of  demarkation  repre- 
sents a  cessation  of  the  movements  of  displacement  in  the  region  over  which 
it  is  found,  and  that  the  same  region  was  planed  down  to  a  base  level  of  ero- 
sion, which  base  level  was  continued  during  the  accumulation  of  these  beds, 
for  it  is  believed  to  be  a  subaerial  conglomerate;  but  should  further  evidence 
prove  it  to  be  a  subaqueous  accumulation  the  plane  of  separation  would  then 
represent  an  epoch  of  change  from  a  period  of  erosion  to  a  period  of  depo- 
sition. This  point  will  be  more  fully  discussed  hereafter. 

BEOWN'S  PAEK  GEOUP. 

This  group  in  Brown's  Park  is  seen  to  lie  unconformably  on  the  Uinta 
Sandstone,  and  all  the  other  Paleozoic,  Mesozoic  and  early  Cenozoic  groups; 
the  plane  of  demarkation,  therefore,  represents  an  epoch  of  change  from  a 
dry  land  to  a  submerged  condition.  The  area  over  which  it  was  deposited 
within  the  region  of  my  study  is  of  small  extent,  but  the  beds  are  known 


EPOCHS  SEPARATING  THE  GROUPS.  63 

to  continue  farther  eastward  beyond  the  belt  examined;  and  it  may  be 
found  as  examination  is  carried  farther  in  that  direction  to  be  conformable 
with  the  next  lower. 

BRIDGER    GROUP. 

The  plane  of  demarkation  between  this  group  and  the  next  in  order  is 
not  always  well  defined.  The  change  from  the  green  sands  or  bad-land 
rocks  to  the  indurated  sandstones  and  limestones  of  the  Upper  Green  River 
is  transitional;  yet  the  epoch  of  change  is  important,  for  the  Upper  Green 
River  attenuates  both  to  the  east  and  west,  and  in  the  latter  direction  it 
entirely  disappears,  so  that  the  Bridger  beds  lie  with  an  apparent  conformity, 
but  actual  unconformity,  on  the  beds  of  the  Lower  Green  River.  This  is 
seen  in  the  vicinity  of  Carter  Station. 

UPPER    GREEN   RIVER    GROUP, 

These  beds  are  interpolated  between  the  Bridger  and  Lower  Green 
River,  as  described  above,  only  in  a  portion  of  the  country  where  the  latter 
two  occur.  The  Tower  Sandstone  which  forms  the  base  of  the  Upper 
Green  River  Group  is  laid  down  unconformably  on  the  Lower  Green 
River,  the  unconformity  being  represented  by  gentle  valleys  of  erosion; 
and  there  seems  to  have  been  a  period  of  erosion  or  dry  land  conditions 
separating  the  Tower  Sandstone  from  the  Plant  Beds  of  the  Upper  Green 
River  also,  and  during  this  dry  land  period  the  sands  of  the  Tower  Sand- 
stone were  eroded  by  rains  and  drifted  by  winds.  After  the  deposition  of 
the  sands,  the  bottom  of  this  great  Green  River  lake  was  left  bare  for  a 
time  and  the  sands  drifted  in  dunes. 

LOWER    GREEN   RIVER   GROUP. 

The  Lower  Green  River  beds  represent  a  period  when  minutely  lami- 
nated bituminous  shales  and  more  massive  limestones  were  deposited,  the 
limestones  prevailing  as  you  descend  in  the  series.  These  beds  are  all 
fresh  water  and  are  separated  from  those  below  by  an  abrupt  plane  of 
stratification  which  marks  a  change  in  the  character  of  the  sediments. 
The  lower  beds  are  soft,  friable,  and  highly  colored  bad-land  sandstones. 
But  this  plane  of  separation  means  something  more.  The  conditions  which 


64  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

prevailed  during  the  deposition  of  the  lower  sandstones  abruptly  changed, 
leaving  a  part  of  the  ancient  lake  dry  and  a  part  submerged,  and  in  this 
submerged  area  the  limestones  and  shales  were  deposited. 

BITTER    CREEK    GROUP. 

The  Bitter  Creek  beds  are  chiefly  bad-land  sandstones.  The  area  of 
lacustrine  deposition  had  its  greatest  expansion  during  this  time.  The 
plane  of  demarkation  separating  it  from  the  next  group  in  order  is  one  of 
great  importance.  When  the  beds  of  the  underlying  group  had  been  laid 
down,  and  before  these  beds  were  formed,  that  movement  began  which, 
carried  on  through  Cenozoic  time,  has  given  us  the  great  Uinta  upheaval. 
There  seems  to  have  been  a  widely  spread  dry  land  condition  separating 
them,  for  on  the  flanks  of  the  mountains  the  lower  Bitter  Creek  beds  rest 
unconformably  on  the  next  group,  and  this  unconformity  is  by  erosion 
and  also  by  angle  of  dip.  This  is  seen  in  several  places.  But  the  move- 
ment in  upheaval  in  the  Uinta  Mountains  was  oscillatory,  and  we  often 
find  the  upper  members  of  the  Bitter  Creek  series  overlapping  the  older 
members,  and  in  extreme  cases  all  of  the  groups  of  Mesozoic  Age  also.  The 
unconformity  between  the  two  groups  away  from  the  mountains  is  simply 
represented  by  erosion.  The  hard,  gray  sandstone,  which  is  the  upper 
member  of  the  Point  of  Rocks  Group,  is  often  seen  to  have  been  eroded 
into  gentle  or  more  abrupt  valleys,  and  the  shales  of  the  Bitter  Creek  Group 
were  carried  into  and  filled  these  valleys. 

These  facts  are  exhibited  in  very  many  places  on  either  flank  of  the 
Uinta  Mountains,  and  on  either  flank  of  the  Aspen  Mountain  fold,  or 
that  fold  the  axis  of  which  is  seen  in  the  Salt  Wells  Basin  ;  yet  there  are 
many  points  where  the  conditions  of  recent  erosion  are  such  that  the  junc- 
tion of  the  two  groups  are  more  or  less  masked,  and  where  the  uncon- 
formity is  less  apparent. 

But  this  epoch  of  change  has  a  more  important  significance.  The 
group  below  I  have  classed  with  the  Mesozoic,  the  group  above  with  the 
Cenozoic,  and  the  change  was  from  marine  to  lacustrine  conditions.  But 
this  change  was  not  abrupt ;  brackish  water  fossils  are  found  in  the  lower 
group  associated  with  marine  forms,  and  with  these  a  few  species  of 


EPOCHS  SEPARATING  THE  GROUPS.  05 

geophila ;  and  brackish  water  fossils,  in  perhaps  a  very  few  instances  of  the 
same  species  with  those  below,  are  associated  with  fresh  water  fossils ;  hence 
the  change  from  marine  to  fresh  water  conditions  seems  not  to  have  been 
abrupt. 

It  will  be  noted  that  the  epochs  of  change  which  separate  the  fresh 
water  Cenozoic  groups  all  represent  a  change  in  character  of  the  sediments, 
and  also  represent  more  or  less  abrupt  contraction  of  the  expanse  of  fresh 
water.  This  was  very  great  during  the  Bitter  Creek  period ;  somewhat 
less  during  the  Lower.  Green  River;  somewhat  less  during  the  Upper; 
perhaps  about,  the  same,  but  less  in  some  directions  and  greater  in  others, 
during  the  Bridger ;  and  when  we  reach  that  point  of  time  represented  by 
the  Brown's  Park  beds  the  area  was  quite  small. 

Those  beds  to  which  the  name  Wasatch  Group  has  been  given,  and 
which  are  found  on  the  eastern  slope  of  the  Wasatch  Mountains,  and 
stretching  out  to  the  eastward  until  they  run  under  Lower  Green  River 
beds,  are  the  western  extension  of  the  Bitter  Creek  beds,  and  hence  the 
name  Wasatch  Group  should  be  dropped.  The  conglomerate  at  the 
bottom  of  what  was  called  the  Wasatch  Group  is  represented  by  the  con- 
glomerates of  the  Bitter  Creek  Group  on  bo'Ji  flanks  of  the  Uinta  Mount- 


6 

ains. 


The  beds  called  the  Washiki  Group  are  the  upper  part  of  the  Bitter 
Creek  series.  I  have  been  unable  to  carry  any  line  of  demarkation 
between  these  beds  over  such  an  extent  of  country  as  would  warrant  their 
separation  from  the  Bitter  Creek  series,  yet  this  may  be  done,  and  in  such 
a  case  the  name  of  Washiki  Group  should  be  retained.  In  the  region  near 
Washiki  Station,  where  they  were  first  seen  by  Dr.  Hayden,  they  are 
exceedingly  conspicuous  by  reason  of  their  brilliant  colors.  Professor 
Cope,  who  saw  them  a  little  farther  to  the  southwest,  thus  appropriately 
describes  them:  "Several  miles  to  the  south  we  reach  another  bench  whose 
bluffy  face  rises  four  or  five  hundred  feet  in  buttress-like  masses,  interrupted 
at  regular  intervals  by  narrow  terraces.  This  line  is  distinguished  by  its 
brilliantly  colored  strata,  extending  in  horizontal  bands  along  the  escarp- 
ment. They  are  brilliant  cherry-red,  white,  true  purple  with  a  bloom- 
si  lade  yellow  and  pea-green,  forming  one  of  the  most  beautiful  displays  I 
5  P  G 


66  SEDIMENTAEY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

ever  beheld.  The  lower  portions  are  of  bright  red,  which  color  predom- 
inates toward  the  west,  where  the  bluffs  descend  to  a  lower  elevation.  I 
found  on  them  the  remains  of  a  turtle  (Emys  eutlmethus  Cope),  and.  some 
borings  of  a  worm  in  a  hard  layer.  On  top  of  these  are  clay  and  slate- 
rocks  of  a  muddy-yellow  color,  with  their  various  ledges  rising  to  perhaps 
five  hundred  feet"  (vide  United  States  Geological  and  Geographical  Survey 
of  Colorado,  page  437). 

These  latter  beds  are  Lower  Green  River  limestones. 

In  the  same  article,  and  immediately  preceding  this  quotation,  Pro- 
fessor Cope  says :  "  At  a  short  distance  to  the  southward  another  line  of 
white  bluffs  extends  across  the  line  of  travel.  This  is  not  more  elevated 
than  the  preceding  one ;  I  only  found  remains  of  tortoises  in  it," 

On  either  flank  of  the  Aspen  Mountain  fold  this  group  of  beds  weath- 
ering white  is  seen,  and  I  have  several  times  at  first  confounded  them  with 
the  Lower  Green  River,  but  the  shales  of  these  beds  are  carbonaceous,  and 
often  contain  more  or  less  lignitic  coal ;  those  of  the  Lower  Green  River 
are  bituminous  and  yield  oil.  The  limestones  of  the  former  are  aggrega- 
tions of  shells  or  shell-marls. 

THE    CRETACEOUS    GROUPS. 

Planes  of  demarkation  in  the  Cretaceous  groups  are  not  easily  drawn. 
The  three  great,  massive  sandstones  of  the  Point  of  Rocks  Group  are  in 
many  places  broken  into  thinner  beds,  and  then  it  becomes  impossible,  with 
our  present  knowledge  at  least,  to  say  to  which  of  these  members  particular 
beds  may  belong.  The  group  below  usually  is  very  thinly  bedded ;  some- 
times, however,  these  beds  are  thicker  and  more  indurated,  and  when  this 
is  the  case  and  the  Point  of  Rocks  Group  is  broken  up  it  is  difficult  to  draw 
a  line  between  the  two  groups.  The  same  difficulty  arises  in  separating 
the  yellow  arenaceous  shales  and  the  black  argillaceous  shales.  Wherever 
the  two  groups  are  exposed  side  by  side,  above  are  seen  thinly  bedded  sand- 
stones and  shales  and  below  are  black,  minutely  laminated  shales,  but  it  is 
very  rare  indeed  that  an  exact  line  can  be  drawn.  In  the  southern  portion 
of  the  province  the  Salt  Wells  beds  are  massive,  and  there  the  separation  is 
more  easily  made.  The  black  shales  of  the  Sulphur  Creek  Group  are 


EPOCHS  SEPARATING  THE  GROUPS.  67 

everywhere  seen  to  rest  upon  a  somewhat  massive  sandstone  which  is  under- 
laid by  bad-land  sandstones,  shales,  conglomerates,  &c.,  with  a  somewhat 
massive  indurated  sandstone  at  the  bottom.  There  seems  to  be  a  very 
decided  change  in  the  paleontology  of  these  groups  from  base  to  summit, 
but  the  fossils,  so  far  as  now  known,  do  not  afford  definite  lines  of  demar- 
kation. 

The  relation  of  these  groups  to  those  established  by  Professors  Meek 
and  Hayden  on  the  Upper  Missouri  is  not  well  determined.  I  have  care- 
fully tried  to  use  their  system  of  grouping  and  have  failed.  A  very 
different  lithologic  series  is  observed,  as  must  be  apparent  from  a  comparison 
of  the  two  sections.  Most  of  the  fossils  are  of  different  species,  and  the 
few  that  can  be  referred  to  the  species  of  Professors  Meek  and  Hayden  in 
that  region  present  contradictory  evidence.  Those  fossils  that  may  be 
referred  to  "No.  2"  are  found  above  fossils  which  may  be  referred  to  "  Nos. 
3  and  4,"  and  as  we  are  tracing  these  bejds  over  broad  areas,  and  from  time 
to  time  collecting  new  fossils,  the  stratigraphic  relations  of  which  should  be 
given  with  their  description,  it  seemed  necessary  that  some  grouping 
should  be  adopted,  and  I  have  given  the  best  I  could  under  the  circum- 
stances. Perhaps  after -the  paleontology  is  more  thoroughly  studied  the 
Upper  Missouri  groupings  can  be  adopted  here,  but  my  present  opinion  is 
that  all  such  attempts  will  prove  futile.  These  opinions  are  based  chiefly 
upon  geological  reasons,  viz :  All  the  evidence  that  has  been  published  by 
Dr.  Hayden  and  members  of  his  corps  concerning  the  Park  Province,  and 
all  my  own  observations  in  that  region,  lead  me  to  the  conclusion  that  a  long 
chain  of  islands  stretched  in  a  northerly  and  southerly  direction  through 
that  region  of  country,  separating  the  Cretaceous  sea  of  the  Plateau  Prov- 
ince from  the  Cretaceous  sea  of  the  Upper  Missouri ;  probably  not  forming 
a  continuous  wall  between  fhe  waters  of  the  two,  but  separating  them  in 
such  a  manner  that  very  different  physical  conditions  prevailed.  It  is  mani- 
fest that  the  Cretaceous  sea  of  the  Plateau  Province  was  fed  chiefly  with 
the  sediments  of  the  Basin  Province,  for  all  the-  Cretaceous  sediments  rap- 
idly attenuate  from  that  old  shore  line  eastward,  and  many  conglomerates 
and  coarse  sandstones  of  Cretaceous  Age  found  there,  are  steadily  replaced 
by  finer  materials  in  an  easterly  direction.  It  is  much  more  probable  that 


68  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

the  Cretaceous  sea  of  the  Basin  Province  was  continuous  with  that  of  Texas. 
The  geological  evidence  seems  to  indicate  this ;  the  evidence  derived  from 
the  fossils  I  leave  for  others  to  discuss. 

FLAMING    GORGE    GROUP. 

The  epoch  separating  the  Flaming  Gorge  Group  from  the  Henry's  Fork 
Group  above  was  one  which  produced  a  change  from  bad-land  sandstones 
to  a  conglomerate.  The  beds  which  overlie  the  conglomerate  contain  marine 
fossils,  but  all  the  fossils  which  we  have  obtained  from  the  upper  portion  of 
the  Flaming  Gorge  Group  are  of  lacustrine  habitat.  The  Mid-Group  Lime- 
stone contains  marine  species,  and  this  is  true  of  the  limestone  at  the  base, 
i.  e.,  the  White  Cliff  Limestone.  The  White  Cliff  period  ended  with  the 
deposition  of  a  massive  cross-bedded  sandstone;  the  Flaming  Gorge  period 
commenced  with  a  deposition  of  limestone;  thus  we  have  an  important 
epoch  of  change  separating  the  two  groups  and  this  is  widely  spread,  for 
it  has  been  seen  wherever  the  junction  of  the  two  groups  has  been  studied. 

WHITE    CLIFF,   VERMILION    CLIFF,    AND    SHINARUMP    GROUPS. 

These  groups  can  be  separated,  only  in  a  very  general  way.  The 
upper  group  is  characterized  near  the  summit  by  a  very  persistent,  massive, 
cross-bedded  sandstone.  The  Vermilion  Cliff  Group  is  also  a  massive  sand- 
stone, and  the  base  of  the  White  Cliff  Group  is  sometimes  composed  of 
massive  sandstones,  sometimes  of  thinly  bedded  sandstones,  and  often  these 
beds  are  highly  gypsiferous,  in  which  case  they  disintegrate  so  rapidly  that 
the  bedding  cannot  be  studied.  The  group  has  yielded  no  fossils. 

The  Vermilion  Cliff  Group  as  a  great  mass  is  easily  recognized  every- 
where, but  just  where  we  should  draw  the  line  above  is  rarely  plain.  Often 
the  massive  sandstones  of  this  bed  are  separated  by  very  irregular  and 
inconstant  layers  or  aggregations  of  hard  calciferous  sandstones.  These 
layers  have  yielded  a  few  imperfectly  preserved  fossils. 

The  summit  of  the  Shinarump  Group  is  a  series  of  gypsiferous  sand- 
stones exceedingly  friable.  They  have  often  been  called  marls,  and  the 
separation  between  them  and  the  massive  vermilion  sandstone  is  never  very 
distinct.  The  difficulty  is  much  greater  where  the  gypsum  disappears  from 


EPOCDS  SEPARATING  THE  GROUPS.  69 

the  lower  beds,  as  it  does  in  places,  where  they  are  also  found  to  be  more 
indurated  and  more  or  less  massive  sandstones.  The  conglomerate  which 
is  found  in  the  middle  of  the  group  is  persistent  over  a  very  large  area,  and 
the  whole  group  is  characterized  throughout  the  entire  province  by  the 
occurrence  of  silicified  wood  in  large  quantities  Sometimes  trunks  of  trees 
from  fifty  to  one  hundred  feet  in  length  are  found.  The  Shinarump  Con- 
glomerate is  usually  very  hard,  and  weathers  in  such  a  manner  as  to  form 
hog-backs  or  cliffs,  and  the  softer  gypsiferous  beds  above,  when  carried 
away  by  rains,  leave  behind  fragments  of  this  silicified  wood,  so  that  the 
Shinarump  Conglomerate  is  often  covered  with  great  quantities  of  this  ma- 
terial. Shinarump  means  literally  "Shin-au-av's  Rock."  Shin-au-av  is  one 
of  the  gods  of  the  Indians  of  this  country,  and  they  believe  these  tree- 
trunks  to  have  been  his  arrows. 

The  plane  of  demarkation  between  the  Shinarump  Group  and  the  sum- 
mit of  the  Carboniferous  is  always  well  marked.  Soft,  gypsiferous  shales  are 
found  at  the  base  of  the  upper  group,  and  cither  a  pure  limestone,  a  cherty 
limestone,  or  a  homogeneous  sandstone,  at  the  summit  of  the  Carboniferous. 
In  places,  however,  a  conglomerate  is  found  at  the  base  of  the  Shinarump 
Group,  its  coarser  fragments  being  composed  of  cherty  limestone  which  con- 
tains Upper  Carboniferous  fossils.  So  in  some  places,  at  least  the  epoch  of 
change  was  a  period  of  erosion.  Flaming  Gorge  Group  contains  Jurassic 
fossils  from*  its  summit  to  its  base,  but  the  fossils  found  in  the  next  three 
groups  below  are  few  and  very  imperfect;  hence  we  cannof  correlate  these 
groups  with  the  general  geological  succession  which  has  been  established 
throughout  the  world,  but  we  know  they  lie  between  the  Jura  above  and  the 
Carboniferous  below. 

THE    CARBONIFEROUS    GROUPS. 

The  grouping*  of  the  Carboniferous  beds  is  fully  set  forth  in  the  section 
on  page  ,r>7.  The  base  of  the  Carboniferous  series  is  not  found  in  Cataract 
Canon,  but  in  the  Uinta  Mountains  these  beds  rest  unconformably  upon 
the  Uinta  Group.  In  the  Grand  Canon,  they  rest  unconformably  upon 
the  Grand  Caiion  Group  and  also  upon  the  crystalline  schists;  hence  in 
both  places  the  plane  of  demarkation  is  important,  and  represents  long 
periods  of  erosion. 


70  SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE 

UINTA    GKOUP. 

The  Uinta  Sandstone  rests  unconformably  upon  the  Red  Creek  Quartz- 
ite;  ten  thousand  feet  of  its  upper  members  are  deposited  unconformably 
against  that  metamorphic  group.  It  is  evident,  also,  that  the  metamorphism 
was  anterior  to  the  deposition  of  the  Uinta  Group,  for  the  beds  of  the  latter, 
especially  near  the  junction,  are  chiefly  made  up  of  fragments  of  the  former; 
hence  the  unconformity  is  very  great. 

The  period  of  erosion  separating  the  sandstones  from  the  Carboniferous 
beds  above  was  sufficient  to  carry  away  at  least  3,000  feet  of  the  Uinta 
Sandstone  in  some  places.  How  much  more  was  carried  away  we  cannot 
say.  To  my  mind  this  suggests  that  the  Uinta  Sandstone  may  be  considered 
Devonian — an  opinion  which  I  would  yield  upon  the  slightest  paleontologic 
evidence  to  the  contrary. 

GRAND  CANON  GROUP. 

The  Grand  Canon  Group  rests  uncomformably  upon  the  crystalline 
schists.  The  evidence  of  this  is  complete,  for  the  lower  sandstones  and 
conglomerates  first  filled  the  valleys  and  then  buried  the  hills  of  schistic 
rocks,  and  these  conglomerates  at  the  base  of  the  group  are  composed  of 
materials  derived  from  the  metamorphic  hills  about ;  and  hence  metamor- 
phism was  antecedent  to  the  deposition  of  the  conglomerates. 

The  plane  of  demarkation  separating  this  group  from  the  Tonto  Group 
is  very  great.  At  least  10,000  feet  of  beds  were  flexed  and  eroded  in  such 
a  manner  as  to  leave  but  fragments  in  the  synclinals.  Then  followed  a 
period  of  erosion  during  which  beds  of  extravasated  material  were  poured 
.over  the  fragments,  and  these  igneous  beds  also  were  eroded  into  valleys 
prior  to  the  deposition  of  the  Tonto  Group. 

Fossils  have  been  found  at  the  base  of  the  Grand  Canon  series,  but 
they  are  not  well  preserved  and  little  can  be  made  of  them.  .  Still,  on  geo- 
logical evidence,  I  am  of  the  opinion  that  these  beds  should  be  considered 
Silurian. 

RED  CREEK  QUARTZITE  AND  GRAND  CANON  SCHISTS. 

These  are  believed  to  be  Eozoic. 


THIS  GROUPING  TENTATIVE.  71 

The  grouping  which  I  have  given  above  should  be   considered  as 
merely  tentative,  and  will  probably  need  some  modification  hereafter ;  it 
may  possibly  need  radical  changes ;  it  would  be  very  unsafe  with  our 
present  knowledge  to  assume  otherwise;  I  know  that* it  will  need  some 
interpolation  in  the  Cretaceous  groups  in  the  southern  part  of  the  province. 
I  should  have  been  pleased  to  have  delayed  its  publication  until  the  entire 
province  had  been  more  thoroughly  surveyed,  but  circumstances  render  it 
necessary  that  I  should  do  something  more  than  make  general  statements 
of  the  methods  and  results  of  the  work  which  I  have  been  doing.     Congress 
has  appropriated  money  from  year  to  year  for  the  work  on  the  representa- 
tion of  a  few  leading  scientific  men  of  the  country  that  the  work  was  being 
done  with  reasonable  skill  and  economy;  but  only  the  few  who  had  time 
and  were  willing  to  examine  the  work  in  manuscript  at  the  office  could 
understand  what  we  were  doing,   and  it  seemed  but  reasonable  that  a 
demand  should  be  made  for  the  publication  of  some  specific  results.     Hav- 
ing concluded  to  commence  the  publication  before  the  province  was  com- 
pletely surveyed,  it  was  absolutely  necessary  that  some  grouping  of  the 
geological  formations  should  be  used.     The  map  must  be  colored  to  show 
the  distribution  of  geological  formations,  arid  of  course  names  must  be  given 
to  the  formations  thus  represented  on  the  map,  and  a  nomenclature  is 
necessary  for  discussion  ;    hence  the  publication  of  the  table.     But  I  shall 
be  willing  to  modify  it  to  any  extent  as  facts  are  collected  which  seem  to 
demand  such  a  change,  whether  such  facts  are  the  results  of  my  own  labors 
or  those  of  others.     Still  I  present  the  table  with  some  degree  of  confidence. 
The  groups  of  rocks  have  been  traced  over  broad  areas,  and  in  the  district, 
the  geology  of  which  I  am  to  describe  in  this  report,  the  grouping  fully 
represents  the  state  of  my  knowledge.     On  account  of  the  discussions  which 
have  arisen  concerning  the  age  of  certain  beds  of  lignitic  coal,  the  plane  of 
demarkation  between  the  Cenozoic  and  Mesozoic  may  subject  me  to  criti- 
cism ;  but,  geologically,  the  plane  is  important,  as  it  represents  a  decided 
physical  change,  and  it  certainly  harmonizes  witli  the  opinion  of  paleontolo- 
gists to  a  degree  that  is  somewhat  surprising.     All  of  the  plants  described 
by  Professor  Lesquereux  and  collected  by  himself  and  others  within  this 
province  have  been  referred  by  him  to  divisions  in  the  Tertiary,  and  are 


72      SEDIMENTARY  GROUPS  OF  THE  PLATEAU  PROVINCE. 

found  in  strata  above  this  physical  break,  and  hence  I  agree  with  him  in 
considering  them  Tertiary. 

In  subdividing  the  Cenozoic  or  Tertiary,  Professor  Lesquereux  has 
attempted  to  draw  very  fine  lines,  dividing  these  beds  into  Eocene  and  Mio- 
cene, and  further  subdividing  each  of  these  two  groups  into  upper,  middle, 
and  lower.  In  doing  this  he  has  done  violence  to  the  stratigraphy,  and 
sometimes  his  upper,  middle,  and  lower  cross  each  other;  but,  in  a  general 
way,  his  Miocene  is  higher  than  his  Eocene. 

All  of  the  fossils. described  by  Mr.  Meek  which  have  been  found  above 
this  physical  break,  he  has  referred  unhesitatingly  to  Tertiary,  and  all  of  the 
fossils  found  below  the  physical  break,  he  has  referred,  unhesitatingly  with 
some,  doubtfully  with  others,  to  the  Cretaceous.  There  is  a  single  excep- 
tion to  this  in  Ostrea  Wyomingensis,  which  is  a  new  species;  and  I  am  sure 
no  paleontologist  would  insist  that  a  new  species  of  ostrea  could  be  used  as 
conclusive  evidence  in  deciding  the  age  of  a  group  of  beds.  That  Mr.  Meek 
did  not  discover  the  physical  break  is  not  strange,  for  he  did  not  see  it. 
When  he  made  his  exploration  in  this  region  he  was  in  ill  health,  and  trav- 
eled "by  rail  from  station  to  station,  stopping  at  these  places  and  examining 
the  nocks  only  in  the  vicinity  of  the  stations.  His  health  would  not  permit 
him  to  make  long  excursions  in  the  country  on  foot,  and  it  was  impossible 
for  him  to  obtain  horses.  He  passed  the  physical  break  above  mentioned 
on  a  railroad  car,  and  his  sections  at  Hallville  and  Point  of  Rocks  are  not 
connected  by  several  hundred  feet,  as  he  states,  and  as  I  have  since  verified 
by  passing  over  the  ground;  and  the  physical  break  is  found  in  the  gap. 
In  like  manner,  on  the  opposite  side  of  the  Aspen  Mountain  uplift,  he  passed 

it  in  the  cars  between  Point  of  Rocks  and  Green  River  Stations. 

* 

The  conclusions  reached  from  a  study  of  the  vertebrate  paleontology 
by  Professors  Leidy,  Marsh,  and  Cope  entirely  harmonize  with  this  division 
of  the  Cenozoic  and  Mesozoic.  There  is  a  single  exception  to  this;  Pro- 
fessor Cope  described  a  dinosaur  found  near  Black  Buttes  Station  as  Creta- 
ceous. I  have  verified  the  determination  of  the  stratigraphic  horizon  by 
examining  the  place  and  finding  other  dinosaur  bones;  but  this  horizon  is 
above  the  physical  break,  and  the  evidence  of  the  dinosaur  seems  to  be  con- 
tradicted by  the  evidence  furnished  by  many  other  species  described  by 
Professor  Cope  from  about  the  same  horizon. 


DIFFERENT  SUCCESSION  OF  COALS.  73 

< 

LIGNITIC  COAL. 

An  examination  of  the  section  will  reveal  the  fact  that  lignitic  coal  is 
found  abundant  from  the  base  of  the  Cretaceous  through  the  recognized 
groups  of  that  division,  and  in  three  of  the  groups  of  the  Tertiary,  giving 
a  horizon  of  11,500  feet.  I  know  of  no  lignite  bearing  group  in  the  Pla- 
teau Province  which  may  be  said  to  be  richer  in  this  product  than  others, 
and  it  would  have  led  to  confusion  to  characterize  any  group  as  the  "Lig- 
nite beds." 

While  lignitic  coal  is  found  in  great  abundance  through  a  long  succes- 
sion of  formations  or  groups,  it  is  rarely  or  never  the  case  that  any  partic- 
ular bed  is  persistent  over  a  great  area.  In  the  Point  of  Rocks  Group  I 
have  at  one  place  found  eleven  beds,  varying  from  ten  inches  to  four  feet  in 
thickness,  and  three  miles  away  where  the  exposure  was  complete  so  that 
no  mistake  could  be  made  except  by  careless  observation  I  have  found 
each  one  of  these  beds  represented  by  carbonaceous  shales  ;  and  facts  simi- 
lar to  this  have  been  noted  in  all  the  other  groups.  It  is  frequently  the 
ca.so  that,  in  studying  the  same  group  at  two  places  separated  by  a  few 
miles,  a  veiy  different  succession  of  coals  will  be  observed.  It  seems  that 
they  were  formed  in  small,  irregular  basins,  from  time  to  time,  beginning 
with  the  Lower  Cretaceous  and  ending  high  up  in  the  Cenozoic. 

Dr.  C.  A.  White  has  prepared  a  catalogue  of  the  species  which,  so  far, 
have  been  collected  in  the  Plateau  Province,  by  myself  and  those  assisting 
me  in  the  work,  and  tabulated  them  in  groups  agreeing  with  the  above 
scheme.  He  has  also  appended  to  each  an  additional  list  of  fossils  collected 
by  others.  The  general  correlation  of  the  section  to  established  successions 
elsewhere  must  at  present  rest  on  the  evidence  furnished  by  this  catalogue. 


III. 


INVERTEBRATE  PALEONTOLOGY  OF  THE  PLA- 
TEAU PROVINCE, 

TOGETHER  WITH   NOTICE  OF  A  FEW   SPECIES  FROM   LOCALITIES  BE- 
YOND ITS  LIMITS  IN  COLORADO, 

BY  CHARLES  A.  WHITE,  M.  D. ' 

WASHINGTON,  D.  C.,  February  1,  187G. 

SIR:  I  have  the  honor  to  present  the  following  preliminary  report  upon 
the  paleontological  collections  made  by  parties  under  your  direction  during 
the  years  1868  to  1875,  inclusive;  more  especially  upon  the  invertebrate 
fossils. 

The  collections  are  large  and  important,  comprising,  besides  the  inver- 
tebrate fossils  noticed  and  described  on  following  pages,  vertebrate  remains 
from  strata  of  the  Carboniferous,  Jurassic,  Cretaceous,  and  Tertiary  periods; 
and  plants  from  those  of  the  Cretaceous  and  Tertiary  periods.  The  plants, 
from  strata  of  the  last  named  period  especially,  are  abundant  and  interest- 
ing, comprising  as  they  do  representatives  of  the  classes  Acrogens,  Endo- 
gens,  and  Exogens,  the  latter  being  greatly  in  excess  of  the  others. 

Among  the  vertebrate  fossils  are  the  remains  of  fishes  (Selachians,  Gan- 
oids, and  Teliosts),  reptiles,  and  mammals.  Besides  these,  a  small  collection 
borrowed  from  Mr.  W.  Cleburn  contains  part  of  the  skeleton  of  a  Passerine 
bird  which  was  discovered  by  him  in  the  Lower  Green  River  Group,  near 
Green  River  Station,  Wyoming  Territory.  Some  of  the  other  discoveries 
of  vertebrate  remains  are  also  worthy  of  notice  here,  among  which  may 
be  mentioned  two  or  three  species  of  teliost  fishes  at  the  base  of  the  Creta- 
ceous series  of  Wyoming  and  Utah,  and  fragments  of  the  skeleton  of  a  very 


GENERAL  OBSERVATIONS.  75 

large  reptile  in  Jurassic  strata  of  Northwestern  Colorado.  The  collection  of 
Mr.  Cleburn  also  contains  two  or  three  species  of  insects. 

The  study  of  the  collections  as  a  whole,  reveals  many  interesting-  facts 
bearing  upon  the  physical  conditions  of  the  regions  examined,  during  the 
deposition  of  the  strata  from  which  they  have  been  collected,  some  of  which 
are  briefly  discussed  on  following  pages.  Among  the  more  important  of 
these  is  the  identification  of  the  marine  genera  Oculina^Phorus,  Dentalium, 
Patella,  Venus,  Mesodesma,  £c.,  from  the  Tertiary  strata  of  Bijou  Basin,  forty 
miles  east  of  Denver,  Colorado.  This  indicates  the  extension  of  open-sea 
marine  deposits  much  farther  into  the  interior  of  the  continent  during  the 
Tertiary  period  than  has  been  previously  known. 

Upon  following  pages  I  present  a  classified  catalogue  of  all  the  inver- 
tebrate species,  following  which  are  descriptions  of  the  new  species.  This 
catalogue  enumerates  two  hundred  and  sixty-two  species  in  all,  forty-eight 
of  which  are  new  to  science,  and  described  herein  for  the  first  time. 

Very  respectfully  yours, 

C.  A.  WHITE. 
Professor  J.  W.  POWELL, 

Geologist  in  charge  of  the  Second  Division  United  States 

Geological  and  Geographical  Survey  of  the  Territories. 

GENERAL  OBSERVATIONS. 

The  fossils  of  the  collections  of  which  the  following  pages  are  occupied 
in  large  part  by  a  classified  and  partially  descriptive  catalogue,  have  been 
obtained  from  strata  of  the  Carboniferous,  Triassic,  Jurassic,  Cretaceous,  and 
Tertiary  periods ;  very  largely  from  the  immediate  vicinity  of  the  Green  and 
Colorado  Rivers  and  from  portions  of  Northern  Utah  and  Southern  Wyom- 
ing. The  areas  from  which  they  have  been  collected  are  very  small  com- 
pared with  that  of  the  great  Plateau  Province,  the  study  of  the  invertebrate 
paleontology  of  which  the  preparation  of  this  report  is  only  a  beginning. 
It  is,  therefore,  too  early  to  draw  final  conclusions  concerning  the  general 
lessons  which  full  collections  from  that  great  region  will  be  sure  to  teach 
us,  or  to  deduce  at  present,  any  very  satisfactory  generalizations;  but  it 
may  not  be  unprofitable  to  mention  some  of  the  facts,  in  their  order,  that 


76 


INVERTEBRATE  PALEONTOLOGY. 


[WHITE. 


have  been  observed  while  making  the  collections  in  the  field  and  also  dur- 
ing- their  more  critical  investigation  in  the  laboratory.  Some  of  these  facts 
have  an  interesting  bearing  upon  the  characteristics  of  the  fossil  faunae  of  the 
periods  which  the  collections  represent,  the  relation  of  those  faunae  to  each 
other,  and  to  both  fossil  and  recent  faunae  of  the  whole  Plateau  Province  as 
well  as  those  of  other  regions. 

For  the  purpose  of  facilitating  reference  to  the  groups  of  strata  which 
have  furnished  the  fossils,  the  following  table  is  introduced.  The  classifi- 
cation of  the  formations  used  in  this  report  is,  for  the  geological  ages  and 
periods,  the  same  as  that  of  Dana's  Manual  of  Geology  (1874,)  and  for  the 
groups  of  strata  of  the  Pleateau  Province,  that  of  Professor .  Powell  in  his 
section  of  the  Uinta  Mountain  region. 


Table  of  the  formations  of  the  Uinta  Mountain  Region. 


Thickness  iu  feet. 


Groups. 


Periods. 


1,800.  Brown's  Park  Group 

2,000.  Bridger  Group 

500.  Upper  Green  River  Group.  ^  Tertiary [  Cenozoic. 

800.  Lower  Green  River  Group . 

3,000.  Bitter  Creek  Group 

1,800.  Point  of  Rocks  Group 

1,800.  Salt  Wells  Group  . 

fc)  AAn  a  i  i       n      i   n  '  Cretaceous  .  . 

2,000.  bulpliur  Creek  Group  . .  -  - 

500.  Henry's  Fork  Group 

1,200.  Flaming  Gorge  Group >  Jurassic /  Mesozoic. 

>  * 

1, 1 00.  White  Cliff  Group 

1,100.  Vermilion  Cliff  Group \.  Triassicl 

1,800.  Shinarump  Group 

1,000.  Upper  Aubrey  Group. 

1,000.  Lower  Aubrey  Group 

«  r^n  ^.    i  -ITT  n  /-M  r  Carbomterous  .  >  Carbomterous. 

2,000.  Red  Wall  Group 

460.  Lodore  Group 


GENERAL  OBSERVATIONS.  77 

In  the  following  brief  review  of  the  faunal  characteristics  of  the  dif- 
ferent groups  represented  in  the  collections  it  is  well  to  consider  how  far 
any  peculiarities  they  present,  different  from  those  which  characterize  their 
position  in  time,  may  have  been  occasioned  by  the  then  and  there  prevail- 
ing physical  conditions  under  which  the  strata  were  accumulated.  Some  of 
those  conditions  were  limited  both  in  extent  and  duration,  but  others  were 
of  a  more  general  and  constant  character.  Almost  all  of  the  fossils  of  these 
collections  are  the  remains  of  mollusks  and  other  aquatic  animals.  It  is  a 
well-known  fact  that  the  character  of  the  material  composing  the  bottom 
upon  which  such  animals  live  constitutes  one  of  the  most  important  elements 
in  their  habitat;  that  not  only  species,  but  even  genera  and  families,  are  often 
separated  from  each  other  in  the  same  waters  by  a  difference  in  the  character 
of  the  material  composing  the  bottom.  It  is  this  gradually-accumulating 
bottom  material  that  has  constituted  the  strata  from  which  we  now  obtain 
the  fossil  remains.  The  prevailing  material  of  the  strata  which  have  furnished 
the  greater  part  of  the  fossils  of  our  collections,  especially  those  of  Mesozoic 
and  Cenozoic  ages,  having  an  aggregate  thickness  of  not  far  from  three  and 
a  half  miles,  is  sand.  The  bottom  of  the  waters,  salt,  brackish,  and  fresh, 
of  all  the  periods  of  both  those  ages,  was  almost  constantly,  either  wholly 
or  in  very  large  part,  composed  of  sand. 

Such  a  condition  as  this,  continued  for  so  long  a  time,  necessarily  pro- 
duced a  marked  effect  upon  the  faunae  of  those  periods,  giving  them  different 
or  modified  characteristics  as  compared  with  those  of  the  same  periods  respect- 
ively in  other  parts  of  the  world. 

Again,  the  evidence  afforded  by  both  the  vertebrate  and  invertebrate 
collections,  and  by  those  of  the  florae  of  all  the  periods  named  in  the 
section  on  a  previous  page,  is  in  favor  of  the  existence  during  that  time  of 
a  warm-temperate  and  uniform  climate.  Furthermore,  the  labors  of  the 
field  geologists  have  shown  that  there  is  a  great  degree  of  conformability 
of  the  strata  of  all  the  subordinate  groups,  from  those  of  the  Carboniferous 
to  those  of  the  Tertiary  periods,  inclusive ;  or  at  least  that  the  cases  of  un- 
conformability  are  few  and  of  comparatively  slight  degree.  So  great  a 
degree  of  uniformity  in  such  important  conditions  as  these  having  prevailed, 
it  is  not  strange  that  the  groups  of  strata  of  the  different  periods  respect- 


78  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

ively  are  not  in  all  cases  clearly  defined  by  faunal  characteristics,  even 
although  they  may  be  separated  by  sufficiently  distinct  physical  characters 
by  the  field  geologist 

The  periods  are,  as  a  rule,  very  clearly  separated  from  each  other  by 
faunal  characteristics,  there  being  a  partial  exception  in  the  case  of  those 
of  the  upper  group  of  the  Cretaceous  period  and  the  lower  group  of  the 
Tertiary.  But  these  facts  will  be  noticed  under  appropriate  heads  on  fol- 
lowing pages. 

Our  investigations  further  show  that  certain  faunal  characteristics  which 
have  hitherto  been  relied  upon  to  fix  the  geological  age  of  strata  of  marine, 
brackish  and  fresh  water  origin,  respectively,  are  not  parallel.  In  other 
words,  our  collections  contain  types  or  forms  of  fresh  and  brackish  water 
origin  that  have  been  regarded'  as  peculiar  to  the  Tertiary  period,  which 
were  obtained  from  strata  that  underlie  those  containing  such  marine  types 
as  are  universally  regarded  as  peculiar  to  Mesozoic  age;  showing  conclu- 
sively, that  so-called  Tertiary  fresh  and  brackish  water  types  and  Cretaceous 
salt  water  types  co-existed.  The  land  shells  also  that  have  been  obtained 
from  strata  herein  classified  as  Cretaceous,  are  of  Tertiary  or  even  of  still 
more  recent  type.  These  facts  have  made  it  especially  difficult  to  fix  the 
period  of  our  terrestrial,  and  fresh  and  brackish  water  fossils  with  satisfactory 
precision,  if  they  were-  new  species  and  obtained  from  unique  and  isolated 
localities. 

A  striking  peculiarity  of  the  strata  of  the  Plateau  Province,  is  the  large 
proportion  among  them  of  fresh  and  brackish  water  deposits.  So  far  as  at 
present  known,  all  the  strata  of  Carboniferous  age  are  of  marine  origin,  the 
first  unmistakably  fresh  water  accumulations  yet  discovered  in  the  Plateau 
Province  being  of  Jurassic  age.  The  only  species  obtained  from  these  fresh 
water  strata  is  a  f/m'o,  which  is  one  of  ordinary  recent  type;  as  is  also 
another  species  of  Unio  and  some  Viviparine  shells,  described  by  Meek  and 
Hayden,  from  the  valley  of  the  Upper  Missouri  River.  These  facts  again 
illustrate  the  comparatively  small  value  that  can  be  placed  upon  fresh  water 
invertebrate  forms  as  indices  of  the  passage  of  geological  time. 

Most  of  the  Mesozoic  strata  were  evidently  deposited  in  water  that  was 
salt  by  virtue  of  having  been  a  part  of,  or  in  communication  with,  the  open 


GENERAL  OBSERVATIONS.  79 

ocean;  but  it  is  not  improbable  that  many  of  the  brackish  water  accumula- 
tions, especially  those  of  late  Cretaceous  and  early  Tertiary  age,  may  have 
been  made  in  land-locked  waters  which  had  their  saline  character  continued 
from  former  times  by  the  leachings  of  surface  drainage,  similar  to  that  of 
Great  Salt  Lake,  but  in  a  far  less  proportionate  degree.  This  idea  is  sug- 
gested by  the  fact  that  the  final  change  to  exclusively  fresh  water  lacustrine 
deposits  was  so  gradual  that  all  the  former  brackish  water  species,  among 
which  no  open-sea  forms  have  been  discovered,  passed  away  without  any 
perceptible  physical  change  in  the  accumulating  strata. 

LOWER  SILURIAN  AGE. 

The  Lower  Silurian  age  is  represented  in  the  collections  only  by  a  very 
few  imperfect  fossils  from  Kwagunt  Valley,  Grand  Canon  of  the  Colorado, 
Arizona.  The  Brachiopod  genera  Lingulella  and  Obolella  are  recognized 
with  a  good  degree  of  certainty,  and,  distributed  through  the  small  masses 
of  rock  which  contain  them,  there  are  apparently  fragments  of  two  or  three 
other  species. 

These  specimens  doubtless  belong  to  the  Primordial  period,  and  possess 
much  interest  as  regards  the  geological  age  of  the  rocks  which  underlie  and 
overlie  them. 

UPPER  SILURIAN  AND  DEVONIAN  AGES. 

The  present  collections  contain  no  fossils  from  strata  of  either  Upper 
Silurian  or  Devonian  age,  but  it  is  not  improbable  that  rocks  of  these  ages 
will  yet  be  discovered  in  the  Plateau  Province.  x 

CARBONIFEROUS  AGE. 

The  collections  contain  fifty  species  from  strata  of  Carboniferous  age, 
much  the  greater  part  of  which  are  from  the  Lower  Aubrey  Group.  A  few 
are  from  the  Upper  Aubrey,  and  a  still  less  number  from  the  Red  Wall 
Group,  while  none  are  reported  from  the  Lodore  Group. 

A  large  proportion  of  all  these  fossils  are  specifically  identical  with  well- 
known  forms  in  the  strata  of  the  Carboniferous  or  Coalmeasure  period  in 
the  States  of  the  Upper  Mississippi  Valley;  and  all  but  two  of  them  belong 
to  such  types  as  we  might  naturally  expect  to  find  in  the  equivalents  of 


80  INVERTEBRATE   PALEONTOLOGY.  [WHITE. 

those  strata.  These  two  belong  to  the  two  genera  respectively  Archimedes 
and  AmplexuSj  the  former  of  which,  especially, 'has  been  regarded  as  an. 
exclusively  Subcarboniferous  genus;  and  yet  they  are  found  in  the  Lower 
Aubrey  Group,  nearly  three  thousand  feet  above  the  base  of  the  Carbonifer- 
ous series,  and  also  above,  and  mingled  with,  types  that  have  not  hitherto 
been  found  in  strata  so  low  as  the  Subcarboniferous 

Few  or  none  of  the  fossils  of  the  collections  are  of  such  a  character  as 
to  suggest  the  Permian  age  of  the  strata  from  which  they  were  obtained, 
not  even  those  of  the  Upper  Aubrey  Group.  I  have  elsewhere  shown* 
that  the  prevalence  of  certain  types  which  have  been  relied  upon  to  prove 
the  Permian  age  of  the  strata  containing  them  may  be  due  to  peculiar 
physical  conditions,  and  I  therefore  regard  it  as  not  improbable  that  the 
time  of  the  Permian  period  may  be  represented  in  the  Plateau  Province 
by  the  Upper  Aubrey  Group,  although  the  distinguishing  types  are  want- 
ing there.  In  view  also  of  the  mixture  which  we  find,  of  "Carboniferous  and 
Subcarboniferous  types  in  the  same  strata,  it  seems  probable  that  the  time 
of  the  whole  Carboniferous  age,  including  its  three  periods,  Subcarbonifer- 
ous, Carboniferous,  and  Permian,  is  collectively  represented  by  the  four 
groups  recognized  in  the  Plateau  Province. 

It  seems  probable,  therefore,  that,  although  some  localities  in  Nevada 
and  Montana  have  furnished  collections  of  almost  exclusively  Subcarbonifer- 
ous types,  we  shall  not,  as  a  rule,  be  able  to  define  in  this  region,  the  three 
periods  into  which  the  age  is  divided  in  other  parts  of  the  world.  It  seems 
also  probable  that  no  divisions  of  the  Carboniferous  strata  of  the  Plateau 
Province  can  be  made  that  will  represent  geological  periods,  well  defined 
upon  paleontological  grounds,  either  corresponding  to  those  already  estab- 
lished in  other  parts  of  the  world,  or  differing  from  them. 

MESOZOIC  AGE. 

TRIASSIC  PERIOD. 

Some  small  collections  of  fossils  which  possess  peculiar  interest  were 
collected  by  Mr.  E.  E.  Howell,  in  1874,  from  the  following  localities  in  Utah: 
At  Toquerville ;  Virgin  River,  south  of  Toquerville ;  near  Workman's 

*  Geology  of  Io\vn.  1870,  vol.  i,  page  24'J, 


GENERAL  OBSERVATIONS-  81 

ranch,  ten  miles  east  of  Toquerville,  and  also  two  miles  west  of  Kanab. 
They  were  obtained  from  the  lower  portion  of  the  Shinarump  Group, 
the  lowest  group  of  Triassic  strata  in  the  Plateau  Province.  The  specimens 
are  all  very  imperfect,  but  the  following  genera  have  been  recognized : 
Pcntacrimis,  RJiynclionella,  Camptonwtes,  and  Myalina.  Besides  these  there 
were  fragments  of  other  conchifers,  the  generic  relations  of  which  are  not 

recognizable.     The  specimens  of  Pentacrinus  consist  only  of  joints  of  the 

• 

column,  like  those  of  P.  asteriscus  Meek  and  Hayden,  so  common  in  the 
Jurassic  strata  of  the  same  region,  and,  indeed,  seem  undistinguishable  from 
those  of  that  species.  So  far  as  can  be  determined,  the  fragments  of  liliyn- 
chonclla  may  be  those  of  the  Jurassic,  R.  gnathopliora  Meek,  and  those  of 
Camptonectes  may  belong  to  any  one  of  the  several  species  known  to  exiat 
in  the  Jurassic  strata  of  the  Plateau  Province.  In  short,  if  the  collections 
had  been  placed  in  my  hands  for  determination,  without  any  statement  of 
their  stratigraphical  position,  I  should  have  referred  them  to  the  Jurassic 
period  with  no  other  doubts  than  those  suggested  by  the  imperfection  of  the 
specimens.  If  their  stratigraphical  position  is  correctly  reported,  which  I 
know  no  reason  to  doubt,  it  seems  certain  that  the  strata  containing  them 

'  C 

ought  to  be  referred  to  the  Jurassic  rather  than  to  the  Triassic  period. 
Before  such  an  important  conclusion  as  this  is  reached,  however,  it  will  be 
necessary  to  secure  more  perfect  and  complete  collections. 

JURASSIC  PERIOD. 

Twenty-seven  species  have  been  recognized  among  the  Jurassic  fossils 
of  the  collections,  at  least  four  of  which  are  new.  With  the  exception  of 

* 

two  Echinoderms  all  the  species  are  molluscan. 

Considerable  interest  attaches  to  the  fact  that  a  species  of  Unio  has 
been  obtained  from  strata  of  this  period  at  Flaming  Gorge,  Utah,  indicating 
the  presence  of  fresh  water  at  that  point  at  one  time  during  the  period. 
The  fact  is  also  of  still  further  interest  as  indicating  that  the  fresh-water 
molluscan  types  which  became  so  prevalent  in  the  Tertiary  period  were 
introduced  early  in  Mesozoic  time  if  not  before. 

CRETACEOUS  PERIOD. 

A  much  larger  number  of  species,  all  of  which  arc  molluscan,  have 

been  obtained  from  strata  of  the  Cretaceous  than  from  those  of  any  one  of 
Or  a 


82  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

the  other  periods  represented  in  the  collections.  The  entire  absence  of  all 
articulate  and  molluscoidean  species  from  all  the  Cretaceous  collections  is 
quite  remarkable.  All  four  of  the  groups  of  strata  are  represented  in  the 
collections,  those  from  the  Henry's  Fork  Group  containing  the  smallest  num- 
ber of  species. 

The  groups  as  a  rule  appear  to  be  separated  by  good  paleontological 
as  well  as  physical  characteristics.  Those  of  the  Henry's  Fork  and  Sulphur 
Creek  Groups,  however,  are  similar,  and  the  dividing  line  between  the  Salt 
Wells  and  Point  of  Rocks  Groups  appears  to  be  indistinct  as  regards  generic 
and  family  types;  but,  with  very  few  exceptions,  the  species  have  not  been 
found  to  pass  from  one  group  to  another.  The  exceptions  thus  far  noticed 
are  those  of  species  that  have*  a  very  wide  geographical  as  well  as  an  un- 
usually great  vertical  range. 

The  Henry's  Fork  and  Sulphur  Creek  Groups,  so  far  as  they  have  been 
examined,  appear  to  have  been  wholly  open-sea  deposits,  no  genera  of 
brackish  water  habitat,  except  Ostrea  and  Anomia,  which  are  also  open-sea 
forms,  having  been  discovered  in  any  of  the  strata.  The  Sulphur  Creek 
Group  is  also  remarkable  for  containing  nearly  all  the  Cretaceous  Cephalo- 
poda of  the  collections;  the  only  exceptions  being  a  specimen  of  Baculites 
ovatus  Say,  from  the'  Salt  Wells  Group  in  the  valley  of  Red  Creek,  Utah, 
and  species  of  Scaphites  from  the  same  group  two  miles  northwestward  from 
Salt  Wells  Station,  Wyoming. 

The  Salt  Wells  Group  is  riot  only  remarkable  for  its  paucity  of  Ceph- 
alopods,  but  also  in  consequence  of  the  fact  that  from  among  its  strata  we 
obtain  the  first  Cretaceous  fresh- water  forms.  Even  among  the  fossils  of 
some  of  its  more  distinctively  marine  strata,  we  obtain  such  forms  as  are 
usually  found  in  the  brackish  and  fresh  water  Cretaceous  and  Tertiary  de- 
posits of  that  region.  The  earliest  of  the  fresh  or  brackish  water  Cretaceous 
deposits  that  have  been  discovered  in  the  Plateau  Province  occurs  among 
strata  of  this  group  near  Coalville,  Utah,  a  fortunate  exposure  of  which 
afforded  Mr.  Meek,  a  few  years  ago,  species  of  the  genera  J7nio,  Cyrena, 
Phym,  Nerit'ma,  &c.,  all  having  a  remarkably  modern  aspect;  but  the  strata 
which  contained  them  are  immediately  overlaid  by  those  which  contain 
Inoccramus,  Grypliea,  Anchura,  and  other  distinctively  Mesozoic  forms. 


GENERAL  OBSERVATIONS.  83 

The  Point  of  Rocks  Group  is  well  represented  in  the  collections  by 
molluscan  species,  all  of  which  are  either  Conchifers  or  Gasteropoda.  Among 
them  are  a  few  land  shells,  many  fresh- water  species,  and  all  but  a  few  of 
the  remainder  belong  to  genera  of  known  brackish-Avater  habitat.  Further- 
more, some  species  of  these  remaining  few  genera  have  been  found  asso- 
ciated with  brackish-water  forms.  It  thus  appears  that  the  formerly  pre- 
vailing- marine  conditions  over  the  region  that  we  "now  call  the  Plateau 

O  O 

Province  began  to  draw  to  a  close  early  in  the  epoch  represented  by  this 
group,  and  had  well  nigh  ceased  at  its  close. 

A  good  illustration  of  this  gradual  change  is  presented  by  the  strata  of 
the  Point  of  Rocks  Group  at  Upper  Kanab,  Utah,  where,  toward  the  base 
of  the  series  exposed,  the  fossils  are  mostly  marine;  above  these  a  greater 
proportion  of  brackish-water  forms  are  introduced;  still  higher  up  fresh-water 
forms  prevail,  and  the  upper  strata  contain  only  fresh  water  and  land  shells; 
the  deposition  of  all  the  strata  having  evidently  been  continuous  and  uninter- 
rupted. 

Among  the  more  interesting  observations  that  have  been  made  in  rela- 
tion to  the  fresh  water  and  land  shells  of  this  epoch  of  the  Cretaceous  period, 
are  those  concerning  the  great  differentiation  of  types  that  had  thus  early 
taken  place.  To  so  great  a  degree  had  this  differentiation  then  attained 
that  the  species  of  Unio,  Helix,  Pliysa,  &c.,  seem  to  have  been  as  diversified 
and  well  developed  as  they  are  at  the  present  time.  Indeed  the  species  of 
these  genera  are  so  closely  like  some  of  those  now  living  that  they  need 
only  the  fresh  condition  of  recent  •  shells  to  remove  all  suspicion  of  their 
great  antiquity  from  the  mind  of  the  casual  observer. 

After  the  foregoing  statements  concerning  the  faunal  characteristics  of 
the  Point  of  Rocks  Group,  one  might  naturally  inquire  for  the  reasons  that 
have  led  to  its  reference  to  the  Cretaceous  rather  than  to  the  Tertiary  period. 
Laying  aside  all  considerations  suggested  by  the  vertebrate  and  floral  remains 
that  have  been  collected  from  its  strata,  the  reply  may  be  briely  stated  thus: 
There  is  no  physical  break  between  this  group  and  the  Salt  Wells  Group 
below  it.  Its  strata  contain  at  least  three  species  of  Inoceramus,  which 
genus  has  never  been  known  in  strata  of  later  date  than  the  Cretaceous 
period.  Odontolmsis,  a  species  of  which  has  been  obtained  from  nenr  the 
summit  of  the  group,  is  regarded  as  a  Cretaceous  genus;  and  in  view  of  the 


84  INVERTED  KATE   PALEONTOLOGY.  [WHITE. 

facts  before  stated,  that  land  and  fresh  and  brackish  water  mollnsks  are 
comparatively  valueless  as  indices  of  the  passage  of  geological  time,  the 
presence  of  no  known  forms  in  its  strata  forbid  the  reference  of  this  group  to 
the  Cretaceous  period. 

CENOZOIC  AGE. 

TERTIARY  PERIOD. 

The  collections  of  Tertiary  fossils  contain  sixt^  species,  exclusive  of 
those  that  were  obtained  from  localities  beyond  the  limits  of  the  Plateau 
Province.  All  of  them  are  either  brackish  or  fresh  water  species ;  the  only 
truly  marine  forms  of  Tertiary  age  being  those  obtained  at  Bijou  Basin, 
Colorado,  which  have  already  been  noticed,  and,  as  they  are  also  described 
and  catalogued  on  following  pages,  they  will  not  be  considered  in  the  fol- 
lowing general  remarks,  which  are  intended  to  apply  mainly  to  that  portion 
of  the  Pro*vince  which  lies  north  of  the  Uinta  Mountains. 

One-half  of  all  these  species  were  obtained  from  the  Bitter  Creek 
Group,  the  lowest  group  of  the  Tertiary  series.  This  difference  in  the  rel- 
ative abundance  of  species  in  the  different  groups  is  of  course  due  primarily 
to  the  conditions  under  which  the  species  lived,  but  evidently  in  large  part 
also  to  the  very  much  greater  geographical  extent,  as  well  as  greater  thick- 
ness, of  this  group  than  of  any  of  the  others.  Among  the  primary  condi- 
tions referred  to,  an  obvious  one  was,  the  continuance  of  the  brackish 
waters,  so  common  in  the  last  epoch  of  the  Cretaceous  period,  into  the  first 
epoch  of  the  Tertiary  in  some  localities,  although  they  seem  to  have  given 
place  to  wholly  fresh  waters  in  other  localities  before  the  close  of  the  Cre- 
taceous period.  Collections  have  been  made  from  these  brackish- water 
Tertiary  strata  at  Black  Buttes.  Point  of  'Rocks,  and  Rock  Spring,  all  in 
the  valley  of  Bitter  Creek,  Wyoming,  and  where  they  reach  a  thickness  of 
from  five  to  seven  hundred  feet  above  the  base  of  the  Tertiary  series.  The 
species  are  clearly  distinct  from  all  others,  either  of  this  or  any  of  the  other 
Tertiary  groups;  but  it  is  not  to  be  denied  that,  although  they  are  also  all 
specifically  distinct  from  any  of  the  species  found  in  the  underlying  Point 
of  Rocks  Group  of  the  Cretaceous  period,  there  is  a  prevalent  similarity  of 
type  between  the  fossils  of  the  two  groups  that  is  apparent  upon  merely 
casual  inspection. 


GENERAL  OBSERVATIONS.  85 

No  true  or  exclusively  marine  species  have  been  discovered  in  these 
brackish-water  Tertiary  strata,  and  it  is  probable  that  the  waters  in  which 
they  were  deposited  were  previously  cut  off  from  the  open  sea,  but  yet 
retaining  to  a  great  degree  their  former  saltness.  The  genera  thus  far  dis- 
covered are  Ostrea,  Anomia,  Corbula,  Corbicula  (Leptesthes),  Cyrena  (Velori- 
tma),  and  Neritina,  besides  the  more  exclusively  fresh-water  genera  Unio, 
Goniolasis,  Viviparus,  Tulotoma,  and  Leioplax? 

The  final  cliange  to  a  wholly  fresh,  from  the  brackish  water  condition, 
which  was  never  to  be  resumed,  was  so  gradual  that  no  physical  difference 
appears  in  the  strata  accumulated  under  both  conditions ;  but  from  and 
after  that  change  a  uniformity  of  molluscan  type  prevailed  through  all  the 
subsequent  epochs  of  the  Tertiary  period,  as  represented  in  the  Plateau 
Province,  that  is  really  remarkable.  It  is  especially  so  if,  as  Professor 
Powell  has  suggested  from  stratigraphical  considerations,  these  Cenozoic 
groups  represent  the  whole  of  what  is  generally  known  as  the  Tertiary 
period.  Here  and  there,  at  different  places  in  each  of  the  Tertiary  groups, 
except  the  Brown's  Park  group,  which,  because  of  its  barrenness  of  fossils, 
is  not  included  in  this  discussion,  a  few  locally  restricted  species  have  been 
found,  amounting  to  a  considerable  number  in  the  aggregate.  But  prevail- 
ing at  numerous  horizons  through  all  these  groups  after  the  brackish -water 
condition  had  ceased,  and  often  in.  great  profusion,  are  the  three  molluscan 
genera  UniOj  Viviparus,  and  Goniobasis,  which  are  almost  invariably  imme- 
diately associated  and  almost  as  invariably  without  other  faunal  associates 
except  occasionally  a  large  discoid  Planorlis. 

The  Unios  are  of  several  species,  which  are  denned  by  characters  simi- 
lar to  those  upon  which  accepted  recent  species  of  the  genus  are  established; 
but  I  have  been  unable  to  discriminate  with  entire  satisfaction  more  than 
one  species  each  of  Goniobasis  and  Viviparus  among  these  prevailing  forms 
in  the  northern  part  of  the  Plateau  Province,  from  the  upper  part  of  the 
Bitter  Creek  Group  to  the  top  of  the  Bridger  Group,  inclusive,  with  the  pos- 
sible exception  of  Viviparus  Wyominfjensis  Meek,  from  the  Bridger  Group. 
The  Planorbis  just  mentioned  I  have  usually  referred  to  P.  spectabUis  Meek, 
but  in  the  Bitter  Creek  Group,  especially  south  of  the  Uinta  Mountains,  a 
variety  occurs  with  fewer  and  broader  volutions,  in  which  respect  it  cor- 


86  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

responds  with  the  description  of  P.  Utahensis  Meek.  The  Vivipanis  and 
Goniobasis  I  have,  in  the  following  catalogue,  referred  respectively  to  F. 
paludinceformis  Hall  sp.  and  G.  tenera  Hall  sp.  Goniobasis  nodiilifera  Meek 
(—  Cerithium  nodidosum  Hall)  and  G.  Carteri  Conrad,  are  regarded  as  syno- 
nyms of  G.  tenera;  and  from  among  the  thousands  of  examples  that  have 
been  collected  from  the  strata  under  discussion,  it  would  be  easy  to  make 
selections  that,  if  found  separately,  would  be  taken  to  indicate  an  equal 
number  of  species,  as  different  from  those  as  they  are  from  each  other. 
Fortunately,  however,  the  specimens  in  all  cases  are  so  abundant  that  other 
selections  may  be  made  showing  full  intermediate  gradations  between  all 
the  species  that  have  been,  and  doubtless  all  that  may  yet  be,  proposed  from 
among  them. 

The  character  and  extent  of  the  variations  of  these  species  in  their 
geographical  distribution,  vertical  range,  and  local  association  will  be  dis- 
cussed in  a  future  report.  It  is,  therefore,  sufficient  now  to  suggest  that 
these  forms  will  present  some  of  the  best  opportunities  for  the  zoologico- 
historical  study  of  certain  species  through  a  great  lapse  of  geological  time 
that  paleontology  has  ever  furnished. 

This  remarkable  uniformity  of  molluscan  types  through  all  the  groups, 
together  with  their  almost  exact  identity  with  recent  types  of  fresh- water 
mollusca,  seems  at  first  view  to  present  an  argument  against  the  supposition 
that  those  Cenozoic  deposits  occupied  the  whole  of  Tertiary  time,  when  con- 
sidered only  in  relation  to  the  invertebrate  remains ;  but  the  slight  value  of 
fresh-water  molluscan  forms  in  such  generalizations  has  already  been  shown. 
If  relied  upon  at  all,  their  modern  aspect  would  seem  to  indicate  late  Ter- 
tiary time  only,  while,  on  the  other  hand,  the  physical  connection  tff  the 
lowest  group  with  the  uppermost  group  of  Cretaceous  strata  is  such  as  to 
leave  no  doubt  that  the  former  represents  the  earliest  epoch  of  Tertiary  time. 

Besides  this  several  of  the  species  found  in  the  brackish-water  layers 
at  the  base  of  the  Bitter  Creek  Group  are  closely  related  to  species  found 
in  similar  deposits  in  Slavonia  and  referred  to  the  Eocene  Tertiary  by 
Brusina.*  (See  "Fossile  Binnen-Mollusken  aus  Dalmatien,  Kroatien,  und 
Slavonien  von  Spiridion  Brusina,  Agram,  1874.") 

*  It  is  mi  interesting  fact  that  these  collections  of  Tertiary  fresh  water  niollusks  iu  Slavonia  possess 
many  Unione  and  Vivipariue  forms  that  arc  of  living  American,  and  not  European  types,  while  all  the 
American  fossil  fresh  water  forms  with  which  I  am  acquainted  are  of  American  recent  types. 


.      GENERAL  OBSERVATIONS.  87 

By  comparing  the  invertebrate  fauna  of  those  fresh  water  Tertiary 
deposits  with  the  faunae  of  existing  fresh  waters  we  observe  the  entire 
absence  from  our  collections  of  all  articulates,  except  a  species  of  Cypris 
and  the  insects  discovered  by  Mr.  Cleburn.  The  list  of  Molluscan  genera 
found  in  those  ancient  lakes  compares  closely  with  those  of  the  great  existing 
American  lakes,  notwithstanding  the  fact  that  the  floral  remains  of  the 
former  indicate  a  uniform  and  much  milder  climate  than  now  exists  in  either 
of  the  two  regions. 

Thus  far  no  well  defined  fluvatile  deposits  have  been  discovered,  but  it 
is  probable  that  those  fresh  water  species  found  among  brackish  water  forms 
constituted  portions  of  the  molluscan  faunae  of  rivers  that  flowed  into  the 
ancient  lakes  or  estuaries,  because  they  are  specifically  different  from,  and 
more  various  than,  those  of  the  purely  fresh  water  deposits.  This  sugges- 
tion is  supported  by  the  well-known  fact  that  the  molluscan  types  of  lakes  are 
fewer  than  those  of  rivers,  while  the  differentiation  is  yet  greater  in  brackish 
and  greater  still  in  marine  waters. 

In  closing  these  remarks  upon  the  Ternary  period  a  question  arises 
similar  to  the  one  briefly  considered  at  the  close  of  the  remarks  upon  the 
Cretaceous  period,  namely  :  Why  has  the  dividing  line  between  the  strata 
of  the  Tertiary  and  Cretaceous  periods  been  drawn  where  it  is  rather  than 
at  some  horizon  either  above  or  below  it  ? 

The  answer  is  nearly  the  same  as  in  the  former  case  There  is  no 
physical  break  in  the  Cretaceous  strata,  from  the  base  of  the  series  to  the 
top  of  the  upper,  or  Point  of  Rocks  Group,  at  which  horizon  there  is  at  all 
observed  points,  extending  over  a  large  region,  considerable  unconforrna- 
bility  by  erosion  of  the  lower  strata  of  the  Bitter  Creek  Group,  upon  the 
upper  strata  of  the  Point  of  Rocks  Group. 

The  separation  of  the  two  periods,  as  represented  by  the  strata  of  the 
.Plateau  Province,  is  a  physical  rather  than  a  paleontological  one.  Upon 
purely  paleontological  ground  it  is  difficult  to  indicate  precisely  where  the 
line  should  be  drawn,  but  it  should  evidently  be  somewhere  near  the  one 
indicated  in  Professor  Powell's  section.  This  being  the  case,  and  it  being 
necessary  to  draw  such  a  line,  it  is  more  rational  to  draw  it  upon  a  line  of 
a  physical  break  than  through  conformable  strata  either  above  or  below  it. 


88  INVERTEBRATE   PALEONTOLOGY.  [WHITE. 


CATALOGUE  OF  THE  FOSSILS  COLLECTED  BY  THE 
VARIOUS  PARTIES  IN  THE  FIELD  DURING  THE 
YEARS  1868  TO  1875,  INCLUSIVE. 

CARBONIFEROUS  AGE. 

CARBONIFEROUS  PERIOD. 
RED  WALL    GROUP. 

1.  Chaetetes.  milleporaceus  Troost. — Gypsum  Canon,   Colorado   River, 
Utah.     The  specimens  have  their  characters  obscured  by  silieification,  but 
they  doubtless  belong  to  this  species.     It  also  occurs  in  the  Lower  Aubrey 
Group.     (See  No.  4.) 

2.  Syringopora  multattenuata  McChesney. — Gypsum    Canon,  Colorado 
River,  Utah. 

3.  CampophyUum f. — Cataract  Canon,   Utah.     A  large  species, 

larger  than  C.  torquium  Owen,  but  the  specimens  are  too  imperfect  for  full 
specific  description. 

LOWER    AUBREY    GROUP. 

4.  Chaetetes  milleporaceus  Troost. — Split  Mountain  Canon,  Green  River, 
Utah.     Also  obtained  from  the  Red  Wall  Group.     (See  No.  1.) 

5.  Fistulipora f. — Confluence  of  Grand  and  Green  Rivers,  Utah. 

Weathered  specimens.    . 

6.  Syringopora ?. — Confluence    of   Grand  and    Green   Rivers, 

Utah.      Specimens  consisting  of  rather   small,   flattened,  or   subspherical 
masses.     Tubes  small  and  much  distorted,  but  imperfect  by  silieification. 

7.  Amplexus  mplirentiformis  White. — Near  Echo    Park  and   at   Split 
Mountain  Canon,  Utah.     Described  on  a  following  page. 

8.  Lopliopliyllum  prolifemm   McChesney.— Confluence  of    Grand   and 
Green  Rivers,  Utah.      Characters  more  nearly  typical  than  those  of  the 
variety  called  Sauridens  found  near  Santa  Fe,  New  Mexico. 

9.  Lithostrotion ?  — York,  Utah ;  west  base  of  Wasatch  range. 

10.  Acervularia f. — Split 'Mountain  Canon,  Green  River,  Utah. 


CATALOGUE  OF  FOSSILS.  89 

11.  Archceocidaris   cratis   White. — Confluence    of    Grand    and    Green 
Rivers,  Utah.     Described  on  a  following  page. 

12.  Arckaocidarw  trudifer  White. — Confluence  of  Grand  and   Green 
Rivers,  Utah.     Specimens  consisting  only  of  imperfect  spines. 

13.  Erisocrinus  typiis  Meek  and  Worthen. — Confluence  of  Grand  and 
Green   Rivers,   Utah.      The  type  specimens  of  Meek  and  Worthen  were 
obtained  from  the  Coal-measures  of  Illinois,  and  consisted  only  of  calyces. 
Ours  shows  about  two  and  a  half  centimeters  in  length  of  the  arms,  each  of 
which  consists  of  a  double,  interlocking  series  of  pieces ;    the  arms  when 
closed  lying  so  closely  together  as  to  leave  only  a  linear  suture  between 
them. 

14.  Scapliiocrinus    carlonarius    Meek    and    Worthen. — Confluence    of 
Grand  and  Green  Rivers,  Utah. 

1  5.  ^Eiipacliycrinus  platylasis  White. — Confluence  of  Grand  and  Green 
Rivers,  Utah.     Described  on  a  following  page. 

16.  Polypora f. — Confluence  of  Grand  and  Green  Rivers,  Utah 

A  large  specimen,  having  unusually  large  fenestrules.     Obverse  side  only 
shown. 

17.  Fenestella ?.— -Near  Echo  Park,  Utah.     Obverse  side  only 

shown. 

18.  Archimedes ?.-— Near  Echo  Park,  Utah.     Specimens  consist 

of  two  axes  only,  one  of  which  is  dextral  and  the  other  sinistral  in  its  volu- 
tions.    They  are,  however,  both  referred  to  one  species. 

]  9.  Discina f. — Bee-hive  Point,  near  Horseshoe  Canon,  Utah. 

A  single  lower  valve. 

20.  Productus  panctatus  Martin. — Confluence    of    Grand   and    Green 
Rivers,  Utah. 

21.  Prodiictus  longispinus  Sowerby  ?. — Near  Echo  Park  and  at  the  con- 
fluence of  Grand  and  Green  Rivers,  Utah. 

22.  Prodiictus  costatus  Sowerby? — Near  Echo  Park,  Utah.     The  speci- 
mens consist  of  the  ordinary  American  forms  generally  referred  to  that 
species,  but  are  probably  distinct  from  it. 

23.  Prod  net  us  costatus  var. — Near  Echo  Park,  Utah.     Like  No.  22  in 


90  INVERTEBRATE   PALEONTOLOGY.  [WHITE. 

essential  characters,  except  that  the  radiating  costse  are  reduced  in  size  to 
that  of  raised  striae. 

24.  Productus  Prattenianus  Norwood. — Confluence  of  Grand  and  Green 
Rivers,  Utah.     Some  of  the  specimens  possess  the  median  row  of  spines  or 
nodes  upon  the  ventral  valve,  like  those  which  Dr.  Newberry  named  P. 
nodosus. 

25.  Productus  semireticulatus  Martin. — Confluence  of  Grand  and  Green 
Rivers,  Utah.     All  the  examples  are  of  the  variety  named  P.  Ivesii  by  Dr. 
Newberry. 

26.  Productus  Nebrascensis  Owen. — Confluence  of  Grand  and   Green 
Rivers,  Utah. 

27.  Productus  muricatus  Norwood  and  Pratten. — Near  Echo  Park,  Utah. 

28.  Productus  multistriatus  Meek. — Confluence  of  Grand  and   Green 
Rivers,  Utah. 

29.  Chonetes  granulifcra   Owen. — Confluence    of    Grand   and    Green 
Rivers,  Utah. 

30.  Chonetes  platynota  White. — Near  Echo  Park,  Utah. 

31.  Hemipronites  crinistria  Phillips. — Near  Echo  Park  and  at  the  con- 
fluence of  Grand  and  Green  Rivers,  Utah.     It  also  occurs  in  the  Upper 
Aubrey  Group.     (See  No.  49.) 

32.  Meekella   striatocostata   Cox. — Confluence    of    Grand    and    Green 
Rivers,  Utah. 

33.  Spirigera  sultilita  Hall. — Confluence  of  Grand  and  Green  Rivers, 
and  near  Echo  Park,  Utah.      Occurs   also  in  the  Upper  Aubrey  Group. 
(See  No.  50.) 

34.  Spirifer  cameratus  Morton. — Confluence  of  Grand  and  Green  Rivers, 
Utah. 

35.  Spirifer  Eockymontanus  Marcou. — Split  Mountain  Canon  and  near 
Echo  Park,  Utah.     Occurs  also  in  the  Upper  Aubrey  Group.     (See  No.  51.) 

36.  Spiriferina  Kentuckensis  Shumard. — Confluence  of  Grand  and  Green 
Rivers,  Utah.     Occurs  also  in  the  Upper  Aubrey  Group  at  the  same  locality. 
(See  No.  52.) 

37.  Avicidopecten  occidentalis  Shumard. — Two  miles  above  Belle  view, 
Utah. 


^ 


CATALOGUE  OF  FOSSILS.  91 

38.  Myalina ?. — Confluence  of  Grand  and  Green  Rivers1,  Utah. 

The  specimens  have  the  aspect  of  M.  rectirvirostris  Meek  and  Worthen,  but 
all  of  them  have  lost  their  beaks.     (See  No.  53.) 

39.  Allorisma  subcuneata  Meek  and  Hay  den? — Confluence  of  Grand 
and  Green  Rivers,  Utah.     The  examples  of  the  collection  agree  with  those 
of  this  species  from  the  typical  localities,  as  given  by  Meek  and  Hayden, 
and  they  also  agree  very  nearly  with  the  description  and  figures  given  by 
Dr.  Newberry  of  A.  capax. 

40.  Edmondia  Aspenwallensis  Meek. — Confluence  of  Grand  and  Green 
Rivers,  Utah. 

41.  Pleurophorns  ?. — Confluence  of  Grand  and  Green  Rivers, 

Utah.     The  species  is  probably  new,  but  the  specimens  are  too  imperfect 
for  full  description. 

42.  Scliizodus   Wheeleri  Swallow. — Confluence  of  Grand   and   Green 
Rivers,  Utah. 

43.  Betterophm  f. — Confluence  of  Grand  and  Green  Rivers, 

Utah. 

44.  Enomplialus  f. — Confluence  of  Grand  and   Green   Rivers, 

Utah.     The  specimens  are  imperfect,  but  are  probably  those  of  E.  luxus 
White. 

45.  Pleurotomaria  excelsa  Newberry. — Confluence  of  Grand  and  Green 
Rivers,  Utah. 

46.  Naticopsis  remcx  White. — Confluence  of  Grand  and  Green  Rivers, 
Utah.     Described  on  a  following  page. 

47.  PliMpsia  -         -f.— Near  Echo  Park,  Utah. 

UPPEE    AUBEEY    GROUP. 

48.  Distinct f. — Bee-hive  Point,  near  Horseshoe  Canon,  Utah. 

49.  Hemipronites  crinistria  Phillips. — Bee-hive  Point,  near  Horseshoe 
Canon,  Utah.     Occurs  also  in  the  Lower  Aubrey  Group.      (See  No.  31.) 

50.  Spirigera  sitbtilita  Hall. — Bee-hive  Point,  near  Horseshoe  Canon, 
Utah.     Occurs  also  in  the  Lower  Aubrey  Group.     (See  No.  33.) 

51.  Spirifer  Rodcymontanus  Marcou. — Bee-hive  Point,  near  Horseshoe 
Canon,  Utah.     Occurs  also  in  the  Lower  Aubrey  Group.     (See  No.  35.) 


92  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

52.  Spiriferina  Kentuckensis  Shumard. — Confluence  of  Grand  and  Green 
Rivers,  Utah.     Also  occurs  in  the  Lower  Aubrey  Group  at  the  same  locality. 
(See  No.  36.) 

53.  Myalina ?. — Confluence  of  Grand  and  Green  Rivers,  Utah. 

Occurs  also  in  the  Lower  Aubrey  Group  at  the  same  locality.     (See  No.  38.) 

54.  JEdniondia f. — Confluence  of  Grand  and  Green  Rivers,  Utah. 

55.  Belleroplion  Montfortianus  Norwood  and  Pratten. — Confluence  of 
Grand  and  Green  Rivers,  Utah.     The  specimens  are  imperfect, 'but  have 
apparently  the  markings  and  other  characteristics  of  this  species  as  it  occurs 
in  the  Coalmeasures  of  the  Mississippi  Valley,  but  the  shell  is  evidently  more 
elongate  or  less  compact. 

56.  Belleroplion  carbonarim  Cox,   var.  subpapillosus  White. — Bee-hive 
Point,  near  Echo   Canon  and  near  Echo   Park,  Utah.     Also  at  Junction 
Mountain  and  near  Diamond  Peak,  Northwestern  Colorado.     This  variety 
differs  from  the  typical  forms  of  the  species  in  its  larger  size  and  in  having 
that  part  of  the  last  volution,  which  is  plain  in  the  typical  shell,  marked 
.with  distant,  slightly-raised  papillae/arranged  in  rows  corresponding  to  and 

continuous  with  the  revolving  striae. 

i  « 

MESOZOIC  AGE. 

JURASSIC  PERIOD. 
FLAMING    GORGE    GROUP. 

57.  Pentacrinus  asterisous  Meek  and  Hayden.— Flaming  Gorge ;  Santa 
Clara  River,  two  miles  below  Gunlock ;  Diamond  Valley ,-  Lower  Potato 
Valley ;   "  White  Hills,"  south  of  Twelve-mile  Creek,  near  Gunnison  ;  three 
or  four  miles  south  of  Kanara,  Utah ;   and  at  the  Vermilion  Hog-backs, 
Northwestern  Colorado.     The  specimens  consist  only  of  joints  of  the  col- 
umn, the  only  part  of  the  species  yet  discovered. 

58.  Spine  of  Echinoid,  too  indefinite  for  either  specific  or  generic  rec- 
ognition.    Santa  Clara  River,  two  miles  below  Gunlock,  Utah. 

59.  Eliynclionella  gnatlioplwm  Meek. — Flaming  Gorge,  Utah,  and  Ver- 
milion Hog-backs,  Northwestern  Colorado. 


CATALOGUE  OF  FOSSILS.  93 

60.  EJiynclionella  Myrina  Whitfield. — Vermilion  Hog-backs,  Northwest- 
ern Colorado. 

61.  Ostrea  strigilecula  White. — Island  Park  and  Flaming  Gorge,  Utah; 
and  Vermilion  Hog-backs,  Northwestern  Colorado.  ' 

62.  Ostrea   (Alcdryonia)  procumbens    White. — Vermilion    Hog-backs, 
Northwestern  Colorado.     Shell  of  moderate  size,  irregularly  ovate  in  mar- 
ginal outline ;  margins  coarsely  dentate ;  valves  moderately  thick,  usually 
attached  by  nearly  the  whole  surface  of  the  lower  one. 

63.  Camptonedes  stygius  White. — Lower  end  of  Long  Valley ;  mouth 
of  Thistle  Creek,  Spanish  Fork  Canon  ;   Upper  Kanab ;  and  three  or  four 
miles  south  of  Kanara,  Utah. 

64.  Camptonedes  bellistriatus  Meek  and  Hayden. — Three  or  four  miles 
south  of  Kanara,  Utah. 

65.  Camptonedes  platessiformis  White. — North  base   of  Aquarius  Pla- 
teau, Southern  Utah.     Resembles  C.  platessa  White  in  its  surface-markings, 
and  C.  Stygius  White  in  its  marginal  outline. 

66.  Gervillia  1. — Nortli  base  of   Aquarius   Plateau,    Southern 

Utah.     Resembles  G.  Montanacnsis  Meek,  but  the  axis  of  the  shell  is  more 
oblique  to  the  hinge-line,  and  the  wing  narrower  than  in  that  species. 

67.  Pinna  -         -?.— Mouth  of  Thistle  Creek,  Spanish  Fork  Canon, 
Utah.     Surface  radiately  ribbed  both  above  and  below  the  median  angle; 
probably  a  new  species,  but  the  specimens  are  too  imperfect  for  satisfactory 
description. 

68.  Modiola  sttbimbricata  Meek. — Vermilion  Hog-backs,  Northwestern 
Colorado. 

69.  Myophoria f. — Island  Park,  Utah.  * 

70.  Trigonia  Americana  Meek. — Flaming  Gorge,  Utah. 

71.  Trigonia  Montanaensis  Meek. — North  base  of  Aquarius   Plateau, 
Utah. 

72.  Trigonia  Conradi  Meek  and  Hayden. — Flaming  Gorge,  Utah. 

73.  Trigonia f. — Santa  Clara  River,  two  miles  below  Gunlock, 

Utah. 

74.  Unio  Stewardi  White. — Flaming  Gorge,  Utah.     Described  on  a  fol- 
lowing page. 


94  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

75.  Trigonella f. — Island  Park,  Utah.     Shells  rather  small-exte- 
rior nearly  perfect,  but  the  hinge  is  unknown,  and  they  are  referred  to  this 
genus  provisionally. 

76.  Undetermined  Concliifers. — Two  species.  Flaming  Gorge ;  north  base 
of  Aquarius  Plateau;    Square-top   Butte,   east  base  of  Aquarius  Plateau, 
Utah. 

77.  Undetermined  Conchifer. — Different  from  No.  76.    Island  Park,  Utah. 

78.  Myacitcs ?. — South  base  of  Thousand-lake  Mountain,  Utah. 

79.  Neritimt-         -?.—" White  Hills",  south  of  Twelve-mile  Creek, 
near  Gunnison,  Utah;  and  Vermilion  Hog-backs,  Northwestern  Colorado. 

80.  Neritinaff  Powelli  White.— Mouth  of  Thistle  Creek,  Spanish  Fork 
Canon,  Utah.     Described  on  a  following  page. 

81.  Undetermined  Gasteropods. — Two  species,  very  small,  and  the  speci- 
mens numerous.     Mouth  of  Thistle  Creek,  Spanish  Fork  Canon,  Utah. 

82.  Eelemnites  densus  Meek  and  Hay  den. — Island  Park  and  Flaming 
Gorge,  Utah;  and  Vermilion  Hog-backs,  Northwestern  Colorado. 

83.  Ammonites  cordiformis  Meek  and  Hayden.— A  small  fragment  of  the 
inner  volutions.     Vermilion  Hog-backs,  Northwestern  Colorado. 

CRETACEOUS    PERIOD. 

HENRY'S  FORK  GROUP. 

84.  Ostrea  prudentia  White.— Head  of  Water-pocket  Can  on,  Southern 
Utah. 

85.  Grypliea  Pitclieri  Morton. — Near  Twin  Mesas;  Upper  Pine  Creek; 
near  Last,Chance  Creek;  head  of  Water-pocket  Canon  and  Lower  Potato 
Valley,  Southern  Utah.     The  specimens  are  numerous,  and  show  the  usual 
extreme  variations.    It  occurs  also  in  the  Sulphur  Creek  Group.    (See  No.  9 7.) 

86.  Exofiyra  Icevinscula  Roemer. — Lower  Potato  Valley  and  south  base 
of  Mount  Killers,  Southern  Utah.    It  occurs  also  in  the  Sulphur  Creek  Group. 
(See  No.  98). 

87.  Exogyra  ponderosa  Roemer. — Head  of  Water-pocket  Canon,  South- 
ern Utah.     It  occurs  also  in  the  Sulphur  Creek  Group,  in  Utah,  and  was 
obtained  from  a  locality  in  Middle  Park,  Colorado.     (See  Nos.  99  and  202.) 


CATALOGUE  OF  FOSSILS.  95 

88.  Plicatula  Jiyclrotheca  White. — Head  of  Water-pocket  Gallon,  South- 
ern Utah.     Described  on  a  following  page. 

89.  Inoceramus  Howelli  White. — Lower  Potato  Valley  and  Upper  Pine 
Creek,  Utah.     Described  on  a  following  page. 

00.  Avicula  linguiformis  Shumard. — Lower  Potato  Valley  and  Sink 
Spring,  Utah. 

01.  Camptoncctes  platcssa  White. — Head  of  Water-pocket  Canon,  South- 
ern Utah. 

02.  Undetermined  Concliifers. — Lower  Potato  Valley,  Utah. 

03.  Cardium f. — Head  of  Water-pocket  Canon,  Southern  Utah. 

• 

A  rather  large  subspinous  species,  probably  new,  but  the  specimens  are  all 
imperfect. 

04.  CaUista  Detvcyi  Meek  and  Hay  den. — Head  of  Water-pocket  Canon, 
Southern  Utah.     The  specimens  consist  only  of  casts  in  sandstone. 

05.  Area  f. — Hea.d  of  Water-pocket    Canon,   Southern   Utah. 

An  elongate  species,  represented  only  by  a  cast  in  sandstone. 

SULPHUR    CREEK    GROUP. 

06.  Ostrea  congesta  Conrad. — Fold,  ten  miles  west  of  Black  Bluff,  Green 
River,  and  Island  Park,  Utah;  base  of  Diamond  Peak  and  near  Vermilion 
Canon,  Northwestern  Colorado.    The  specimens  from  the  last-named  locality 
are  unusually  large,  and  a  few  of  them  were  found  free,  but  most  of  them 
were,  as  usual,  found  attached  to  fragments  of  Inoceramus  deformis.     The 
species  occurs  also  in  the  Point  of  Rocks  Group,  Utah,  in  Western  Kansas, 
and  in  Middle  Park,  Colorado.     (See  Nos.  150  and  200.) 

07.  Gryplica  Pitrlieri   Morton. — Near   Black  Bluff,   on   Green   River; 
Upper  Kanab;  fold,  ten  miles  west  of  Black  Bluff  and  Sink  Spring,  Utah. 
It  also  occurs  in  the  Henry's  Fork  Group.     (See  No.  85.) 

08.  Exogyra  l&viuscida  Roemer. — Upper  Kanab,  and  near  Black  Bluff, 
011  Green  River,  Utah.     Occurs  also  in  Henry's  Fork  Group,  Utah.     (See 
No.  86.) 

00.  Exogyra  ponderosa  Roemer. — Upper  Kanab,  Utah.  It  occurs  also 
in  Henry's  Fork  Group,  Utah,  and  in  Middle  Park,  Colorado.  (See  Nos. 
87  and  202.) 


90  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

100.  Inoceramus  deformis  Meek. — Fold  ten  miles  west  of  Black  Bluff  on 
Green  River,  and  Island  Park,  Utah.      Base  of  Diamond  Peak  and  near 
Vermilion  Canon,  Northwestern  Colorado.     It  accurs  also  at  the  base  of  the 
Point  of  Rocks  Group,  near  Coalville,  Utah;  in  western  Kansas,  and  in  Mid- 
dle Park,  Colorado.     (See  Nos.  167  and  203.) 

101.  Lucina  subundata    Hall  and  Meek. — Upper  Kanab  and  Thistle 
Creek,  Utah.     A  species  probably  identical  with  this  occurs  in  the  Salt  Wells 
Group  at  Coalville,  Utah.     (See  No.  132.) 

102.  Leiopistlia  Meckii  White. — Upper  Kanab  and  Sink  Spring,  Utah. 

103.  Turnus  splienoideus  White. — Upper  Kanab,  Utah.     Described  o^n 
a  following  page. 

104.  Lunatia  concinna  Hall  and  Meek. — Sink  Spring,  Utah. 

105.  AncJmraruida  White. — Upper  Kanab,  tltah,     Described  on  a  fol- 
lowing page. 

106.  Anclmra  proldbiata  White. — Upper  Kanab  and  Sink  Spring,  Utah. 
Described  on  a  following  page. 

107.  Turritetta  Uvasana  Conrad.- — Upper  Kanab,  Utah. 

108.  Cassiope  Whitfieldi  White. — Upper  Kanab,  Utah. 

109.  Pseudobuccinum  Nebmsccnse  Meek  and  Hay  den. — Upper  Kanab, 
Utah. 

110.  Baadites  ovatus  Say.- — Fold  ten  miles  west  of  Black  Bluffs,  Green 
River,  Sink  Spring,  near  Twin  Mesas,  and  Upper  Kanab,  Utah.     Occurs 
also  in  the  Salt  AVells  Group.     (See  No.  157.) 

111.  Scapliites   Warreni  Meek  and  Hay  den. —Fold  ten  miles  west  of 
Black  Bluff,  Green  River,  Utah. 

112.  Ammonites  Woolgari  Mantelll — Last  Chance  Creek,  Utah. 

113.  Ammonites f. — Fold  ten  miles  west  of  Black  Bluff,  Green 

River,  Utah.     This  species  is  of  the  type  of  A.  Woolgari,  but  the  volutions 
are  proportionally  deeper  and  the  umbilicus  smaller  than  in  that  species. 

114.  Ammonites f. — Upper  Kanab,  Utah,    Specimens  imperfect, 

but  they  indicate  a  species  quite  different  from  any  others  in  the  collections. 

115.  Bucliiceras  Swallovi  Shumard. — Upper  Kanab,  Utah. 

116.  Helicoceras  f. — Near  Twin  Mesas,  Utah,     The  specimens 

show  two  rows  of  long  dorsal  spines  and  a  crenulated  or  transversely  undu- 


CATALOGUE  OF  FOSSILS.  97 

lated  surface.     They  are  so  compressed  in  shale  that  the  character  of  the 
coil  is  not  shown,  and  may,  therefore,  probably  belong  to  the  genus  Crioceras. 

117.  Helicoceras ?. — Upper  Kanab,  Utah.    A  fragment,  different 

from  No.  116. 

118.  Belemnitella ?. — Upper  Kanab,  Utah,  and  Sulphur  Creek, 

Bear  River  City,  Wyoming.     The  specimens  are  more  or  less  imperfect,  but 
they  closely  resemble,  and  are  probably  identical  with,  B.  mucronata,  so 
common  in  the  Cretaceous  strata  of  New  Jersey. 

119.  Serpula  intrica  White. — Upper  Kanab,  Utah. 

SALT    WELLS    GROUP. 

120.  Ostrea  solemscus  Meek. — Coalville,  Lower  Salina  Can  on,  and  near 
False  Creek,  Utah;  Bear  River  City,  and  Hilliard  Station,  Wyoming. 

121.  Ostrea  (Alectryonia)  sannionis  White.     Weber  Valley,  near  Coal- 
ville, Utah.     Described  on  a  following  page. 

122.  Ostrea  (Alectryonia f. — Near  False  Creek,  Southern  Utah. 

The  specimens  are  fragmentary,  but  they  indicate  an  unusually  large  species 
of  this  subgeiius. 

123.  GrypJiea ?. — Coalville,  Utah.    The  specimens  are  imperfect, 

but  they  seem  to  indicate  a  species  materially  different  from  G.  Pitclieri 
Morton. 

124.  Anomia f. — Coalville,  Utah. 

125.  Inoceramus  problematicus  Schlotheim. — Lower  Salina  Canon  and 
Coalville,  Utah;  Bear  River  City,  Wyoming. 

126.  Inoceramus f. — Two  miles  northwestward  from  Salt  Wells 

Station,  Wyoming. 

127.  Inoceramus  Gilberti  White. — Near  Last  Chance  Creek,  Southern 
Utah.     Described  on  a  following  page. 

128.  Avicula  (Pseudoptera)  rliytopliora  Meek. — Coalville,  Utah. 

129.  Modiola  (Bracliydontes)  multilinigcra  Meek. — Coalville,  Utah. 

130.  Area  Coalvillensis  White. — Coalville,  Utah.     Described  on  a  fol- 
lowing page. 

131.  Macrodon  f. — Coalville,  Utah.     A  rather  large,  elongate 

species,  represented  only  by  a  sandstone  cast. 

7  p  G 


98  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

132.  Lucina  subundata  Hall  and  Meekt — Coalville,  Utah.     Apparently 
identical  with  that  species.     (See  No.  101.) 

133.  Cardium  curtum  Meek  and  Hayden. — Coalville,  Utah. 

134.  Cardium  subcwrtmn  Meek. — Coalville,  Utah. 

135.  Cyrena  (Vcloritina)  securis  Meek. — Coalville,  Utah.     Mr.  Meek's 
types  were  from  the  Salt  Wells  Group,  Sulphur  Creek,  Bear  River  City, 
Wyoming,  but  ours,  although  imperfect,  seem  to  belong  to  the  same  species. 

136.  Cyrena  (Veloritina)  erecta  White. — Upper  Kanab,  Utah,  and  Hil- 
liard  Station,  Wyoming.     Described  on  a  following  page. 

137.  Tellina  (Arcopagia)  Utaliensis  Meek. — Coalville,  Utah. 

138.  Tellina  modesta  Meek. — Coalville,  Utah. 

139.  Mactra  arenaria  Meek. — Coalville,  Utah. 

140.  Corbula  nematopJiora  Meek. — Coalville,  Utah. 

141.  Corbula-         -f.— Coalville,  Utah. 

142.  Martesia  -         -  f. — Coalville,  Utah.   • 

143.  Pliysa ?. — Coalville,  Utah.      One  imperfect  example  only 

was  found.     It  was  associated  with  shells  of  marine  type  only,  but  it  never- 
theless seems  to  possess  the  characters  of  a  true  Pliysa. 

144.  Neritina  Bannisteri  Meek. — Hilliard  Station,  Wyoming.     The  type 
specimens  of  this  species  were  obtained  by  Mr.  Meek  from  among  brackish 
and  fresh  water  forms  near  Coalville,  Utah.     No  fresh,  or  exclusively  brack- 
ish water  forms  were  found  associated  with  our  examples,  although  the  geo- 
logical horizon  is  doubtless  identical,  or  very  nearly  so,  at  the  two  localities. 

145.  Neritina  pisum  Meek  — Coalville,  Utah. 

146.  Neritina  (Velatella)  patelliformix  Meek. — Coalville,  Utah. 

147.  Lunatia  Utahensis  White. — Coalville,  Utah.     Described  on  a  fol- 
lowing page. 

148.  Anchura  fusiformis  Meek. — Coalville,  Utah,  and  Sulphur  Creek, 
Bear  River  City,  Utah. 

149.  TurnteUa  micronema  Meek. — Coalville,  Utah. 

150.  Tiirritella  Coalmllensis  Meek. — Coalville,  and  ten  miles  southeast 
of  Kanara,  west  of  Cone  Mountain,  Utah. 

151.  Eidimella  funicula  Meek. — Coalville,  Utah. 


CATALOGUE  OF  FOSSILS.  99 

152.  Turbonilla  (Chemnitzia)  Coalvillensis  Meek. — Coalville,  Utah,  and 
Hilliard  Station,  Wyoming. 

153.  Gyrodes  depressa  Meek. — Coalville,  Utah. 

154.  Fusus  (Neptunea)  Gabli  Meek. — Coalville,  Utah. 

155.  Fusus  (Neptunea)  Utahensis  Meek. — Coalville,  Utah. 

156.  Admetopsis  gregaria  Meek. — Coalville,  Utah. 

157.  Baculites  ovatus  Say. — Below  "Wall  Rock,"  basin  of  Red  Creek, 
Utah.    Occurs  most  commonly  in  the  Sulrjhur  Creek  Group.     (See  No.  110.) 

158.  Scaphites f. — Two  miles  northwestward  from  Salt  Wells 

Station,  Wyoming. 

POINT    OF    EOCKS    GKOUP. 

159.  Ostrea  congesta  Conrad. — Near  the  base  of  the  group,  Coalville, 
Utah.     The  species  occurs  most  abundantly  in  the  Sulphur  Creek  Group  of 
the  Plateau  Province ;  but  it  has  a  wide  geographical,  as  well  as  a  great 
stratigraphical,  range.     (See  Nos.  96  and  200.) 

160.  Ostrea  -         -  f. — Upper  Kanab,  Utah. 

161.  Ostrea ?. — Bear  River  Vallev,  near  Mellis  Station,  where 

*/   * 

it  is  associated  with  fresh  and  brackish  water  mollusks. 

162.  Ostrea  Coalvillensis  Meek. — Coalville,  Utah. 

163.  Ostrea  insecura  White. — Two  miles  west  of  Point  of  Rocks,  Wyo- 
ming.    Described  011  a  following  page. 

164.  Anomia  gryphorhynclms  Meek. — Two  miles  west  of  Point  of  Rocks, 
Wyoming. 

165.  Inoceramus f. — Top  of  Aspen  Mountain,  but  near  the  base 

of  the  group,  Wyoming.     The  species  is  nearly  like  /.  sagensis  Owen,  but 
the  specimens  are  too  imperfect  for  specific  identification. 

166.  Inoceramus —       -f. — Upper  Kanab,  Utah.     It  has  the  general 
aspect  of  both  I.  Howelli  and  I. '  fragilis,  but  differs  from  both  in  essential 
details. 

167.  Inoceramus  deforms  Meek. — Near  the  base  of  the  group,  Coalville, 
Utah.     This  species  is  most  common  in  the  Sulphur  Creek  Group,  but  it 
has  a  wide  geographical,  as  well  as  a  great  vertical,  range.     (See  Nos.  100 
and  203.) 


100  INVERTEBRATE   PALEONTOLOGY.  [WHITE. 

J68.  Unio  gonionotus  White. — Sevier  Cliffs,  twelve  miles  above  Pan- 
guitch,  Utah.  Described  011  a  following  page. 

169.  Unio f. — Associated  with  the  last  (168),  but  differs  from 

it  in  its  more  convex  beaks  and  in  wanting  the  plications  of  that  species. 

170.  Unio  l)elliplicatus  Meek. — Bear  River  Valley,  near  Mellis  Station, 
Wyoming. 

171.  Unio  Vetustus   Meek. — Bear  River  Valley,   near  Mellis    Station, 
Wyoming,  and  Canon  of  Desolation,  Utah. 

172.  Cyrena    (Veloritina)    Durkeei    Meek. — Bear    River   Valley,    near 
Mellis  Station,  Wyoming. 

173.  Cyrena  (Veloritina)  f. — Upper  Kanab,  Utah. 

174.  Cyrena  (Veloritina)  cytlieriformis  Meek  and  Hayden. — Two  miles 
west  of  Point  of  Rocks,  Wyoming. 

175.  Corbula  undlfera  Meek. — Rock  Spring,  Wyoming. 

176.  Corbula  pyriformis  Meek. — Bear  River  Valley,  near  Mellis  Station, 
Wyoming. 

177.  Corbula  tropidopliora  Meek. — Two  miles  west  of  Point  of  Rocks, 
Wyoming. 

178.  Limncea ?. — Upper  Kanab,  Utah. 

179.  Limnaa f. — Bear  River  Valley,  near  Mellis  Station,  Wyo- 
ming. 

180.  Planorbis    (Batliyompliahis)    Kanabcnsis   White. — Upper    Kanab, 
Utah.     Described  on  a  following  page. 

181..  Pliysa  Kanabensis  White. — Upper  Kanab,  Utah.  Described  on  a 
following  page. 

]  82.  Pliysa ?. — Bear  River  Valley,  near  Mellis  Station,  Wyo- 
ming. 

183.  Pliysa ?. — Upper  Kanab,  Utah.     Associated  with  No.  181, 

but  it  is  a  larger  species,  and  has  a  much  shorter  spire,  the  volutions  of 
which  are  more  broadly  shouldered  on  the  proximal  side  of  the  suture. 

184.  Rliytopliorus  prisons  Meek. — Bear  River  Valley,  near  Mellis  Sta- 
tion, Wyoming. 

185.  Rliytopliorus  Meekii  White. — Bear  River  Valley,  near  Mellis  Sta- 
tion, Wyoming.     Described  on  a  following  page. 


CATALOGUE  OF  FOSSILS.  101 

186.  Helix f. — Canon  of  Desolation,  Utah. 

187.  Helix  Kanabensis  White. — Upper  Kanab,  Utah.     Described  on  a 
following  page. 

188.  Goniobasis  nitidula  Meek. — Bear  River  Valley,  near  Mellis  Station, 
Wyoming. 

189.  Goniolasis  insculpta  Meek. — Rock  Spring,  AYyoming. 

190.  Goniobasis  chrysalis  Meek. — Bear  River  Valley,  near  Mellis  Sta- 
tion, Wyoming. 

191.  Goniobasis  Nebrascensis  Meek  and  Hayden. — Canon  of  Desolation, 
Utah. 

192.  Goniobasis  chrysaloidea  White. — Bear   River  Valley,  near  Mellis 
Station,  Wyoming.     Described  on  a  following  page. 

193.  Goniobasis  Cleburni  White. — Bear  River  Valley,  near  Mellis   Sta- 
tion, Wyoming1.     Described  on  a  following  page. 

1 94.  Goniobasis f. — Upper  Kanab,  Utah. — It  is  associated  with 

Pyrgulifera  humerosa  Meek,  and  bears  some  resemblance  to  G.  Cleburni,  but 
it  has  a  proportionally  much  shorter  spire.     The  specimens  are  all  sand- 
stone casts. 

195.  Pyrgulifera  humerosa  Meek. — Bear  River  Valley,  near  Mellis  Sta- 
tion, Wyoming,  and  Upper  Kanab,  Utah. 

196.  Viviparus  Panguitchensis  White. — Sevier  Cliffs,  twelve  miles  above 
Panguitch,  and  Upper  Kanab,  Utah. 

197.  Campeloma   macrospira   Meek. — Bear  River  Valley,    near   Mellis 

• 

Station,  Wyoming,  and  Canon,  of  Desolation,  Utah. 

198.  Odontobasis  buccinoidea  White. — Two  miles  west  of  Point  of  Rocks, 
Wyoming.     Described  on  a  following  page. 

199.  Turritella ?. — Upper  Kanab,  Utah.     Near  the  base  of  the 

group. 

CRETACEOUS  FOSSILS  FROM  BEYOND  THE  LIMITS   OF   THE   PLATEAU 

PROVINCE. 

200.  Ostrea  congesta  Conrad. — Western  Kansas,  and  near  Platte  Canon, 
Middle  Park,  Colorado. 

201.  Ostrea  -        -I.— Near  Platte  Canon,  Middle  Park,  Colorado.     A 
large  biconvex  species. 


102  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

202.  Ezogyra  ponderosa  Roemer. — Near  Platte  Canon,  Middle  Park, 
Colorado. 

203.  Inoceramus  deformis  Meek. — Western  Kansas. 

204.  Inoceramus  ( Volviceramus)  exogyroides  Meek.     Three  miles  north- 
eastward from  Hot  Springs,  Middle  Park,  Colorado. 

205.  Inoceramus   BaraUni    Morton  ?. — The  specimens  vary  from  the 
typical  forms  in  being  deeper  from  hinge-line  to  base. 

206.  Avicula  Parkensis  White. — South  of  Grand  River,  Middle  Park, 
Colorado.     Described  on  a  following  page. 

207.  Heteroceras ?. — Three    miles    northwestward    from    Hot 

Springs,  Middle  Park,  Colorado.     The  species  is  represented  by  a  fragment 

only. 

CENOZOIC  AGE. 

TERTIARY    PERIOD. 

BITTER    CREEK    GROUP. 

208.  Ostrea  Wyomingensis  Meek. — Point  of  Rocks,  Black  Buttes,  and 
Rock  Spring,  Wyoming. 

209.  Ostrea  arcuatllis  Meek. — Black  Buttes,  Wyoming. 

210.  Anomia f. — Black  Buttes,  Wyoming. 

211.  Unio  proplieticus  White. — Black  Buttes,  Wyoming.     Described  on 
a  following  page. 

212.  Unio  petrinus  White. — Black  Buttes,  Wyoming.     Described  on  a 
following  page. 

213.  Unio f. — Black  Buttes,  Wyoming.    A  large  massive  species, 

but  much  shorter  than  U.  petrinus,  with  which  it  is  associated. 

214.  Unio f. — Near  Evanston,  Wyoming.     A  large,   elongate 

species,  but  the  specimens  are  too  imperfect  for  specific  recognition  or  de- 
scription. 

215.  Unio  Leanus  Meek! — South  Fork  of  Vermilion  River,  near  Dia- 
mond Peak,  Northwestern  Colorado. 

216.  Unio  brachyopisthus  White. — Black  Buttes,  Wyoming.     Described 
on  a  following  page. 

217.  Corbicula  (Leptesthes)  fracta  Meek. — Black  Buttes,  Wyoming. 


CATALOGUE  OF  FOSSILS.  103 

218.  Cyrena  (Veloritina)  Bannisteri  Meek. — Point  of  Rocks,  Wyoming. 

219.  Pisidium  saginatum  White. — Almy  Coal  Mines,  near  Evanston, 
Wyoming.     Described  on  a  following  page. 

220.  Corbula  subwndata  White. — Point  of  Rocks,  Wyoming.     Described 
on  a  following  page. 

221.  Corbula  crassitelliformis  Meek. — Black  Buttes,  Wyoming. 

222.  Planorbis  Utahensis  Meek. — South  base  of  Pine  Valley  Mountains, 
Utah.     (See  No.  245,  and  also  general  remarks  on  page  85.) 

223.  Planorbis ?. — Almy  Coal  Mines,  near  Evanston,  Wyoming. 

224.  Planorbis  (Bathyomplialus)  f. — Almy   Coal    Mines,    near 

Evanston,  Wyoming.     The  specimens  consist  of  fragments  only,  but  they 
indicate  a  large,  well  marked  species  of  this  subgenus. 

225.  Physa  pleromatis  White. — Southeast  flank  of  Quien  Hornet  Mount- 
ain, Wyoming ;  east  base  of  Pine  Valley  Mountains,  Utah,  and  many  other 
localities. 

226.  Physa 1. — Almy  Coal  Mines,  near  Evanston,  Wyoming. 

227.  Helix L — Almy  Coal  Mines,  near  Evanston,  Wyoming. 

228.  Helix-        -?.— Different  from  No.  227.    East  base  of  Pine  Valley 
Mountains,  Utah. 

229.  Helix  peripheries  White. — South  base  of  'Pine  Valley  Mountains, 
Utah.     Described  on  a  following  page. 

230.  Neritina  volvilineata  White. — Black  Buttes,  Wyoming.     Described 
on  a  following  page. 

23 1 .  Goniobasis  tenera  Hall  sp. — Various  localities.     (See  Nos.  247,  259, 
and  265,  and  also  general  remarks  on  page  85.) 

232.  Goniobasis ?. — Almy  Coal  Mines,  near  Evanston,Wyoming. 

This  species  is  related  to  G.  Ncbrascensis  Meek  and  Hayden,  but  is  more 
elongate. 

233.  Goniobasis  Wyomingcnsis  Meek. — Black  Buttes,  Wyoming. 

234.  Hydrobia  recta  White. — Almy  Coal  Mines,  near  Evanston,  Wyoming. 
Described  on  a  following  page. 

235.  Hydrobia    Utahensis  White. — West  base   of   Mu-si-ni-a   Plateau, 
1,000  feet  below  its  summit,  Utah. 


104  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

236.  Viviparus  plicappressus  White. — Black    Buttes,  Wyoming.     De- 
scribed on  a  following1  page. 

237.  Viviparus  trocliiformis  Meek. — West  base  of  Mu-si-ni-a  Plateau, 
tain,  1,000  feet  below  its  summit. 

238.  Viviparus  trochiformis  var. — Associated  with  No.  337. 

239.  Viviparus  paludincBformis  Hall  sp. — Various  localities.     (See  Nos. 
248,  260,  and  266,  and  also  general  remarks  on  page  85.) 

240.  Tidotoma  Tlwmpsoni  White. — Black  Buttes,  Wyoming.     Described 
on  a  following  page. 

241.  Leioplaxf  turricula  White. — Black  Buttes,  Wyoming.     Described 
on  a  following  page. 

LOWER    GEEEN    EIVER    GROUP. 

242.  Unio  Shoslionensis  White. — West  side  of  Snake  River,  six  miles 
north  of  Junction  Mountain ;  cliffs  four  miles  northwestward  from  the  head 
of  Vermilion  Canon  and  Dry  Mountains,  Northwestern  Colorado.     Described 
on  a  following  page.     It  occurs  also  in  the  Upper  Green  River  Group.     (Sec 
No.  249.) 

243.  Unio ?, — Two  miles  east  of  Lawrence  Station,  Wyoming. 

Base  of  the  group. 

244.  Spliarium f. — Four  miles  northeastward  from  the  head  of 

Vermilion  Canon,  Northwestern  Colorado. 

245.  Planorbis  Utaliensis  Meek. — West  side  of  Snake  River,  six  miles 
north  of  Junction  Mountain,  Northwestern  Colorado.     It  occurs  also  in  the 
Bitter  Creek  Group.     (See  No.  222,  and  also  general  remarks  on  page  85.) 

246.  Helix  riparia  White. — Eight  miles  below  Green  River  Station, 
Wyoming.     Described  on  a  following  page. 

247.  Goniobasis  tenera  Hall  sp. — Various  localities.     (See  Nos.   231, 
259,  and  265,  and  also  general  remarks  on  page  85.) 

248.  Viviparus  paludinceformis  Hall  sp. — Various  localities.     (See  Nos. 
239,  260,  and  266,  and  also  general  remarks  on  page  85.) 

UPPER    GREEN    RIVER    GROUP. 

249.  Unio  Shoslionensis  White. — Henry's   Fork  and  Alkali  stage-sta- 


CATALOGUE  OF  FOSSILS.  105 

tion,  Wyoming-.     Described  on  a  following  page.     It  occurs  also  in  the 
Lower  Green  River  Group.     (See  No.  242.) 

250.  Unio ?. — Henry's  Fork,  Wyoming. 

251.  SptwBrium ?. — Alkali  stage-station,  twenty-one  miles  north- 
ward from  Green  River  Station,  Wyoming. 

252.  Planorbis  spectabilis  Meek. — Henry's  Fork,   Wyoming.     Occurs 
also  in   the  Bridger  Group.     (See  No.  263,  and  also  general  remarks  on 
page  85.) 

253.  Planorbis 1. — Henry's  Fork,  Wyoming.     A  small  species, 

marked  with  fine  revolving  lines. 

254.  Pliysa ?. — Henry's  Fork,  Wyoming. 

255.  Succinea papillispira  White. — Alkali  stage-station,  Wyoming.     De- 
scribed on  a  following  page. 

256.  Helix   f. — Henry's    Fork,    Wyoming.     A   small    species, 

somewhat  resembling  the  recent  H.  perspective 

257.  Piqm  incolata  White. — Henry's  Fork,  Wyoming.     Described  on  a 
following  page. 

258.  Pupa  arenula  White. — Henry's  Fork,  Wyoming.     Described  on  a 
following  page. 

259.  Goniobas-is  tenem  Hall  sp.- — Various  localities.     (See  Nos.  231,  247, 
and  265,  and  also  general  remarks  on  page  85.) 

260.  Viviparus  paludinaformis  Hall  sp. — Henry's  Fork  and  Alkali  stage- 
station,  Wyoming,  and  various  other  localities.     At  the  first-named  locality 
the  specimens  are  below  the  usual  average  size.     (See  Nos.  239,  248,  and 
266,  and  also  general  remarks  on  page  85.) 

261.  Cypris f. — Henry's  Fork,  Wyoming.     This  species  seems 

to  be  specifically  different  from  C.  Leidyi  Evans  and  Shumard. 

BRIDGES    GROUP. 

262.  Unio  Haydeni  Meek. — Near  Fort  Bridger,  Wyoming. 

263.  Planorbis  spectabilis  Meek. — Henry's  Fork,  east  of  Fort  Bridger, 
and  six  miles  west  of  Badland  Mountains,  Wyoming.     Occurs  also  in  the 
Upper  Green  River  Group.     (See  No.  252,  and  also  general  remarks  on 
page  85.) 


106  INVERTEBRATE   PALEONTOLOGY.  [WHITE. 

264.  Pliysa  Bridgerensis  Meek. — Henry's  Fork,  east  of  Fort  Bridger, 
Wyoming. 

265.  Goniobasis  tenera  Hall  sp. — Various  localities.     (See  Nos.   231, 
247,  and  259,  and  also  general  remarks  on  page  85.) 

-  266.   Viviparus  paludinceformis  Hall  sp. — Various  localities.     (See  Nos. 
239,  248,  and  260,  and  also  general  remarks  on  page  85.) 

267.  Viviparus  Wyomingensis  Meek. — Near  Fort  Bridger,  and  six  miles 
west  of  the  Cameo  Mountains,  Wyoming.     This  seems  to  be  specifically  dis- 
tinct from  the  prevailing  form  that  I  have  referred  to  V.  paludinceformis, 
being  a  larger,  thinner,  and  more  inflated  shell. 

BROWN'S  PAKK  GKOUP. 

268.  Physa ?. — This  is  the  only  invertebrate  species  discovered 

in  the  strata  of  this  group, 'and  all  the  examples  of  it  are  too  imperfect  to 
serve  as  the  basis  of  a  specific  description. 

TERTIARY    FOSSILS    FROM    BEYOND    THE    LIMITS    OF    TIIE    PLATEAU 

PROVINCE. 

269.  Flustra f. — Bijou  Basin,  forty  miles  east  of  Denver,  Colo- 
rado.    The  specimens  are  found  incrusting  the  oyster,  No.  270. 

270.  Ostrea f. — Bijou  Basin,  forty  miles  east  of  Denver,  Colo- 
rado.    The  species  is  a  very  large  one ;  the  largest  example  is  nearly  a 
foot  in  length  and  proportionally  broad. 

271.  Cyrena  (  Veloritina) f. — Fresh-water  Tertiary  deposits,  Crow 

Creek,  Colorado,  where  it  was- found  associated  with  No.  278. 

272.  Corbicula  Powetti  White. — Bijou  Basin,  forty  miles  east  of  Denver, 
Colorado.     Described  on  a  following  page. 

273.  Venus f. — Bijou  Basin,  forty  miles  east  of  Denver,  Colo- 
rado.    The  specimens  are  fragmentary,  but  the  hinge  is  shown. 

274.  Petricola f. — Burrows  only.     Bijou  Basin,  Colorado. 

275.  Mesodesma  Bishopi  White. — Bijou  Basin,  forty  miles  east  of  Den- 
ver, Colorado.     Described  on  a  following  page. 

276.  Dentalmm f. — Bijou  Basin,  Colorado.     A  small  longitudi- 
nally striated  species. 


DESCRIPTIONS  OF  NEW  SPECIES.  107 

277.  Dentalium f. — Bijou  Basin,  Colorado.     Much  like  No.  276, 

except  that  its  surface  is  marked  only  by  encircling  lines  of  growth. 

278.  Melania   Larunda  White. — Crow   Creek,   Colorado,  where  it  is 
associated  with  No.  271.     Described  on  a  following  page. 

279.  Patella f. — Bijou  Basin,  Colorado.     A  single  small  exam- 
ple. 

280.  Phorus  exoneratus  White. — Bijou  Basin,  Colorado,  forty  miles  east 
of  Denver,  Colorado.     Described  on  a  following  page. 

281.  Cerithium  f. — Bijou   Basin,    Colorado.     A   single,    small, 

imperfect  example. 

t 

DESCRIPTIONS  OF  NEW  SPECIES  OF  INVERTEBRATE  FOS- 
SILS FROM  STRATA  OF  THE  CARBONIFEROUS,  JURASSIC, 
CRETACEOUS,  AND  TERTIARY  PERIODS. 

CARBONIFEROUS  PEKIOD. 
Radiata. 
Actinozoa. 

Genus  AMPLEXUS  Sowerby. 

Amplexus  zaphrentiformis  (sp.  nov.).— Corallum  having  the  external  aspect 
of  Zaplirentis  rather  than  of  Amplexus,  being  elongate-conical  in  form,  more 
or  less  curved  and  tapering  to  a  point  or  small  pedicil  at  the  base;  epitheca 
well  developed,  having  its  surface  marked  by  the  usual  concentric  wrinkles 
and  lines  of  growth,  and  with  longitudinal  lines  marking  the  position  of  the 
septa,  the  latter  not  being  very  distinct;  calyx  circular  or  subcircular,  the 
plain  portion  of  the  surface  at  its  bottom  equal  to  one-third  or  more  of  the 
diameter  of  the  corallum ;  septal  fossette  well  developed,  situated  at  the  con- 
cave side  of  the  corallum;  septa  thirty  or  forty  in  number,  rather  strong; 
transverse  plates  numerous,  well  developed,  somewhat  irregular,  and  ending 
exteriorly  against  a  moderately  well  developed  external  wall,  which  is  dis- 
tinct from  the  epitheca  proper.  This  external  wall  contains  no  vesicles  and 
apparently  consists  of  solid  coralline  substance. 


108  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

The  largest-  example  in  the  collection  is  nearly  nine  centimeters  in 
length,  the  calyx  having  a  diameter  of  twenty-five  millimeters;  but  the 
average  size  of  nearly  one  hundred  examples  is  considerably  less. 

This  species  differs  from  all  other  species  of  Amplexus  known  to  me  in 
its  zaphrentoid  form,  but  its  plain  calyx-bottom,  its  broad  transverse  plates, 
and  the  absence  of  a  vesicular  zone,  leave  no  doubt  as  to  the  propriety  of 
referring  it  to  the  genus  Amplexus. 

Position  and  locality.— Lower  Aubrey  Group;  Split  Mountain  Canon,  and 
near  Echo  Park,  Utah. 

Echinodermata. 

Genus  EUPACHYCRINUS  Meek  and  Worthen. 

• 

Eupachycrinus  platybasis  (sp.  nov.). — Calyx  nearly  flat;  basal  pieces 
small,  concealed  by  the  first  joint  of  the  column,  which  is  proportionally 
large ;  subradial  pieces  rather  small  or  of  medium  size,  their  inner  ends  also 
covered  by  the  first  joint  of  the  column;  judging  from  the  portion  of  them 
that  is  visible,  they  are  all  of  nearly  regular  rhombic  outline;  first  radials 
much  broader  than  long,  broadly  convex  from  side  to  side  and  abruptly 
convex  from  within,  outward,  all  of  them  ending  with  a  regular  obtuse  angle 
between  the  subradial  pieces  except  the  left  anterior  one,  the  angle  of  which 
is  made  a  little  irregular  by  the  interposition  of  the  second  anal  plate ;  first 
anal  piece  of  the  same  size  and  shape  as  the  subradial  pieces;  second  anal 
piece  apparently  nearly  as  large  as  the  first,  between  which  and  the  left 
anterior  first  radial  piece  it  is  interposed,  reaching  nearly  as  far  inward  as 
the  first  radial  piece  does,  and  at  which  point  it  ends  with  an  acute  angle; 
plates  all  massive.  Remainder  of  the  structure  unknown.  Sutures  all  linear  > 
surface  nearly  or  quite  smooth. 

Diameter  of  the  calyx,  eighteen  millimeters. 

This  species  differs  from  the  typical  forms  of  the  genus  in  the  extreme 
flatness  of  its  calyx,  but  the  arrangement,  number,  and  general  character  of 
the  pieces  composing  it  leave  no  doubt  as  to  the  propriety  of  referring  it  to 
Eupacliycrinus. 

Position  and  locality. — Lower  Aubrey  Group;  confluence  of  Grand  and 
Green  Rivers,  Utah. 


DESCRIPTIONS  OF  NEW  SPECIES.  109 

Genus  ARCILEOCIDARIS  McCoy. 

Arcliceocidaris  cratis  (sp.  nov.). — Spines  slender,  gradually  tapering  from 
base  to  point;  shaft  ornamented  with  sharp,  distant  spinules,  each  about  one 
and  a  half  millimeters  long  and  pointing  strongly  upward ;  basal  ring  promi- 
nent, plain,  except  the  fine  crenulation  of  its  edges,  and  situated  very  near 
the  proximal  end  of  the  spine.  Surface  apparently  smooth. 

Length  about  six  centimeters;  diameter  just  above  the  basal  ring1  nearly 
three  millimeters;  diameter  of  basal  ring  about  four  millimeters. 

The  collections  of  the  Geological  Survey  of  Nebraska  in  the  cabinet 
of  the  Smithsonian  Institution  contain  a  single  spine  of  this  species,  which, 
together  with  that  of  these  collections,  is  all  that  is  known  of  the  species. 
It  may  be  readily  recognized  by  its  smooth,  slender  shaft,  with  its  distant, 
sharp  spinules. 

Position  and  locality. — Lower  Aubrey  Group;  confluence  of  the  Grand 
and  Green  Rivers,  Utah. 

Mollusca. 

Gasteropoda. 

Genus  ^NATICOPSIS  McCoy. 

Naticopsis  remex  (sp.  nov.). — Shell  of  ordinary  size,  very  oblique  when 
adult,  by  the  elongation  and  enlargement  of  the  last  volution ;  volutions 
about  four,  convex,  increasing  rapidly  in  size,  the  last  one  large  and  much 
produced ;  spire  small  and  short ;  suture  impressed.  Surface  marked  by 
the  usual  lines  of  growth,  and,  although  that  of  the  specimens  in  the  collec- 
tion is  not  very  well  preserved,  there  are  some  indications  of  the  presence 
of  faint  revolving  striae  also. 

Length  across  the  longest  diameter  of  the  aperture  and  body  volution 
of  an  average-sized  specimen,  twenty-three  millimeters ;  short  diameter  of 
the  same,  seventeen  millimeters. 

Position  and  locality. — Summit  of  the  Lower  Aubrey  Group ;  confluence 
of  the  Grand  and  Green  Rivers,  Utah. 


110  INVERTEBltATE  PALEONTOLOGY.  [WHITE. 

JURASSIC     PERIOD. 

Mollusca. 

Conchifera. 

Genus  UNIO  Retzius. 

Unio  Stewardi  (sp.  nov.). — From  the  Jurassic  strata  at  Flaming  Gorge 
of  Green  River,  near  the  northern  boundary  line  of  Utah,  some  portions  of 
a  moderately  large  Unio  were  obtained  that  belong  to  an  undescribed 
species.  The  valves  are  broadly  oval  in  marginal  outline,  broadly  but 
somewhat  uniformly  convex ;  beaks  very  near  the  anterior  end ;  test 
massive ;  surface  apparently  marked  only  by  the  ordinary  lines  and  imbri- 
cations of  growth ;  cardinal  and  lateral  teeth  both  strong ;  the  lower  lateral 
tooth  of  the  left  valve,  and  also  that  part  of  the  hinge  of  the  right  valve 
against  which  it  shuts,  both  strong  and  rounded  into  the  cavity  of  each 
valve  respectively,  and  both  ^nd  posteriorly  by  abruptly  rounded  ends. 

Length  of  largest  example,  eight  and.  a  half  centimeters ;  height,  sixty- 
two  millimeters. 

Compared  with  U.  nucalis  Meek  and  Hayden,  the  only  other  species 
of  the  genus  known  to  me  from  American  Jurassic  strata,  it  is  larger,  more 
massive,  the  beaks  placed  more  anteriorly,  and  the  cardinal  and  lateral 
teeth  more  massive. 

Specific  name  given  in  honor  of  Mr.  J.  F.  Steward,  of  Piano,  111.,  its 
discoverer. 

Gasteropoda. 

Genus  NERITINA  Lamarck. 

Neritini  ?  ?  Powelli  (sp.  nov.).— Shell  moderately  large,  obliquely  sub- 
ovate  in  outline ;  volutions  about  three  or  three  and  a  half,  rapidly  increas- 
ing in  size,  the  last  one  much  expanded ;  spire  depressed,  the  apex  scarcely 
appearing  by  side  view  of  the  shell ;  suture  slightly  impressed ;  aperture 
large,  broadly  subcircular  or  subtetrahedral ;  a  broad  rounded  revolving 
prominence  extends  around  the  volutions,  nearer  to  their  distal  than  prox- 
imal side,  and  another  less  prominent  one  between  the  first  one  and  the 
suture ;  the  first  one,  especially,  gives  a  degree  of  angularity  to  the  last 
volution  and  to  the  margin  of  the  aperture. 


DESCRIPTIONS  OF  NEW  SPECIES.  HI 

Surface  marked  by  ordinary  lines  of  growth,  and  also  by  somewhat 
prominent  folds  parallel  with  them;  the  folds  being  stronger  upon  the 
revolving  prominences  before  mentioned  than  elsewhere,  and  disappear 
upon  the  under  surface  of  the  shell. 

Greatest  diameter  of  the  largest  example,  twenty-eight  millimeters ; 
breadth  of  the  same,  twenty  millimeters ;  height,  the  aperture  resting  upon 
the  table,  fifteen  millimeters. 

By  carefully  digging  out  the  stony  filling  I  have  been  unable  to  find 
any  trace  of  a  thickened  inner  lip  such  as  characterizes  the  Neritidse,  but 
the  body  seems  to  be  small,  simple,  and  without  even  a  proper  columella. 
The  shell  has  the  external  aspect  of  a  member  of  the  family  Neritidae,  but 
it  is  not  without  much  hesitation  that  I  refer  it  to  the  genus  Neritina. 
Indeed,  this  reference  of  it  is  made  only  provisionally  until  further  investi- 
gation can  be  made.  This  disposition  of  it  is  made  partly  because  it  seems 
properly  referable  to  no  other  established  genus,  and  partly  in  view  of  the 
facts  published  by  Brinkhorst  in  his  Monog.  Gast.  et  Ceph.  de  la  Craie  Sup. 
du  Limbourg,  1861.  In  that  work  he  describes  and  figures  two  species, 
Nerita  rugosa  Hoeninghaus,  and  N.  parvula  Brink.,  which  he  shows  to  have 
been  so  fossilized  that  the  callus  which  formed  the  thickened  inner  lip  was 
entirely  removed  by  a  natural  process  of  solution,  leaving  the  remainder  of 
the  shell  intact,  and  in  a  condition  similar  to  that  of  the  species  here 
described  as  regards  the  absence  of  an  inner  lip,  but  natural  casts  of  his 
species  showed  that  they  originally  possessed  a  well  developed  one.  No 
such  casts  have  been  found  with  our  shells,  and  it  is  not  improbable  that 
they  were  originally  without  any  thickened  inner  lip. 

If  so,  our  shell  cannot  be  properly  referred  to  any  genus  with  which  I 
am  acquainted,  arid  in  case  further  investigation  shall  leave  no  doubt  that 
the  shells  have  not  been  changed  from  their  original  character,  I  propose  for 
it  the  generic  name  of  Lyosoma. 

Specific  name  given  in  honor  of  Prof.  J.  W.  Powell,  geologist  in  charge 
of  the  Second  Division  United  States  Geological  and  Geographical  Survey. 

Position  and  locality. — Flaming  Gorge  Group;  mouth  of  Thistle  Creek, 
Spanish  Fork  Canon,  Utah. 


112  INVERTEBRATE   PALEONTOLOGY.  [WHITE. 

CRETACEOUS   PERIOD. 
Mollusca. 

Conchifera. 

Genus  OSTREA  Linnaeus. 
Subgenus  ALECTEYONIA  Fischer. 

Ostrea  (Alectryonia)  sannionis  (sp.  nov.).— Shell  rather  small,  alate  at 
both  sides  of  the  beak,  irregularly  subquadrate  in  marginal  outline,  its 
longitudinal  axis  curved,  the  convexity -of  the  curve  being  forward,  almost 
as  wide  across  the  alations  as  at  the  base,  but  constricted  in  the  middle ; 
beaks  small,  not  prominent,  directed  slightly  backward ;  lower  valve  mod- 
erately convex ;  scar  of  attachment  at  the  beak  small  or. absent ;  ligament- 
area  short,  rather  broad ;  its  longitudinal  furrow  shallow  but  well  defined, 
transversely  striated,  and  pointing  obliquely  backward ;  posterigr  alation 
narrower  than  the  anterior  one,  and  a  little  longer  than  the  corresponding 
alation  of  the  other  valve ;  muscular  scar  comparatively  large,  situated 
nearly  mid-length  of  the  valve  and  near  the  posterior  margin,  curved- 
spatulate  in  outline,  the  broadest  end  being  toward  the  base  of  the  shell ; 
upper  valve  nearly  flat,  but  in  other  respects  corresponding  with  the  lower. 

Surface  of  both  valves  marked  by  the  ordinary  lines  and  lamellatioris 
of  growth  common  to  the  genus  and  by  numerous  creiiulated  radiating  pli- 
cations, four  or  five  of  which  upon  each  valve  reach  the  base  of  the  shell, 
giving  that  margin  a  coarsely  zigzag  or  toothed  condition.  The  other  pli- 
cations are  smaller  and  die  out  at  the  sides  of  the  shell  and  upon  the  alations. 

Length  from  base  to  beak  of  a  large  example  thirty-eight  millimeters ; 
breadth  near  the  front  the  same;  across  the  wings,  thirty- three  millimeters. 

This  is  one  of  the  most  distinctly  defined  species  of  the  genus  known 
to  me,  and  numerous  examples  of  it  show  that  it  was  subject  to  compara- 
tively little  variation. 

.  Position  and  locality. — Near  top  of  Salt  Wells  Group ;  Weber  Valley, 
near  Coalville,  Utah. 

Ostrea  insecura  (sp.  nov.). — Shell  rather  small,  thin,  elongate-suboval 
in  outline  when  adult,  suboval  or  snbcircular  when  young ;  beaks  and  area 


DESCRIPTIONS  OF  NEW  SPECIES.  J  13 

small;  scar  of  attachment  usually  small  and  sometimes  absent;  surface  com- 
paratively smooth  for  an  oyster ;  a  few  faint  radiating  plications  appearing 
upon  some  examples.  Length  of  largest  example  nearly  five  and  a  half 
centimeters  ;  breadth  twenty-nine  millimeters. 

Position  and  locality. — Point  of  Rocks  Group;  two  miles  west  of  Point 
of  Rocks,  Wyoming. 

Genus  PLICATULA  Lamarck. 

Plicatida  liydrotlieca  (sp.  nov.). — Shell  of  ordinary  size,  irregularly  sub- 
ovate  in  marginal  outline;  beaks  rather  narrow ;  lower  valve  broadly  con- 
vex ;  hinge  teeth  well  developed ;  upper  valve  nearly  flat,  or  slightly 
concave  near  the  beak. 

Surface  of  both  valves  marked  by  small,  slightly  raised  radiating 
plications,  which  are  crenulated,  a  little  irregular  and  more  or  less  distinct 
upon  all  parts  of  the  surface  of  both  valves. 

Length,  three  centimeters ;  greatest  breath,  twenty-four  millimeters. 

Position  and  locality. — Henry's  Fork  Group;  head  of  Water-pocket 
Canon,  Southern  Utah. 

Genus  INOCERAMUS  Sowerby. 

Inoceramus  Gilberti  (sp.  nov.). — Shell  irregularly  suboval  in  marginal 
outline,  the  transverse  diameter  being  greater  than  the  vertical;  front  flat- 
tened; valves  nearly  or  quite  equal,  both  being  gibbous  and  sometimes  quite 
ventricose;  umbones  broad  and  elevated;  beaks  very  near  the  front,  incurved 
but  not  projecting  beyond  the  front  margin ;  front  nearly  straight  vertically, 
and  forming  nearly  a  right  angle  with  the  hinge;  front  margin  rounded 
below  to  the  basal  margin,  which  is  broadly  convex  for  more  than  half  the 
length  of  the  shell;  postero-basal  margin  extending  obliquely  upward,  with 
a  slight  emargination  to  the  posterior  extremity,  which  is  abruptly  rounded 
to  meet  the  downward-sloping  postero-dorsal  margin;  dorsal  margin  straight, 
its  length  equaling  more  than  half  the  long  diameter  of  the  shell. 

Upon  each  valve  there  is  an  obscure  radiating  shallow  furrow  or  de- 
pression extending  from  the  umbonal  region  to  the  postero'-basal  border  and 

ending  at  the  emargination  there,  before  mentioned. 
SPG 


114  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

Surface  marked  by  the  usual  lines  of  growth,  and  also  by  numerous 
extravagant  and  irregular  concentric  folds  or  wrinkles. 

This  species  belongs  to  the  section  of  the  genus  that  Brongniart  has 
designated  under  the  name  of  Catillus.  It  is  a  peculiarly  well-marked  species 
and  easily  distinguished  from  all  others  found  in  the  rocks  of  the  great 
Rocky  Mountain  region. 

Transverse  length  of  an  average-sized  specimen  seven  and  a  half  centi- 
meters; height  from  base  to  hinge,  five  centimeters.  Specific  name  given 
in  honor  of  its  discoverer,  Mr.  G.  K.  Gilbert,  geologist  of  one  of  the  survey- 
ing parties. 

Position  and  locality. — Salt  Wells  Group;  near  Last  Chance  Creek, 
Southern  Utah. 

Inoceramus  Howelli  (sp.  nov.). — Shell  of  medium  size,  obliquely  and 
irregularly  suboval  in  marginal  outline,  the  vertical  diameter  being  greater 
than  the  transverse;  both  valves  having  considerable  convexity,  that  of  the 
left  valve  greater  than  the  other;  beaks  narrowed,  prominent,  the  prominence 
of  the  left  one  greater  than  the  other,  both  of  them  elevated  above  the 
hinge  line,  and  also  curving  forward  beyond  the  front  of  the  shell;  front 
flattened,  extending  almost  straight  downward  from  the  front  end  of  the 
hinge,  with  which  it  forms  nearly  a  right,  or  slightly  obtuse,  ang-le.  Antero- 
basal  margin  abruptly  rounded  to.  the  base;  basal  margin  short;  postero- 
basal  margin  extending  obliquely  upward  to  the  posterior  extremity,  straight- 
ened or  slightly  emarginate;  posterior  extremity  abruptly  rounded  to  meet 
the  almost  straight  postero-dorsal  margin. 

Between  the  axis  of  the  body  of  the  shell  and  the  postero-dorsal  margin 
there  is  upon  each  valve  a  rather  broad,  shallow,  but  more  or  les*s  distinct 
furrow  or  depression,  extending  from  the  umbonal  region  to  the  postero- 
basal  margin,  and  ending  at  the  emargination  before  mentioned.  There  is 
also  a  distinct  alation  upon  each  valve,  separated  from  the  body  portion  by 
a  tolerably  well-defined  auricular  furrow. 

Surface  marked  by  the  ordinary  lines  of  growth,  and  also  by  moder- 
ately distinct  concentric  folds,  but  the  surface  has  a  rather  smoother  aspect 
than  is  usual  with  species  of  this  genus.  Height  of  an  average-sized  example, 


DESCRIPTIONS  OF  NEW  SPECIES.  115 

from  base  to  beaks,  seven  and  a  half  centimeters;  greatest  breadth,  which 
is  near  the  base,  five  centimeters;  length. of  hinge,  thirty-seven  millimeters. 

This  shell  somewhat  resembles  I.  fragllls  Hall  and  Meek,  but  differs 
from  it  in  possessing  the  shallow  radiating  furrow  upon  the  body  of  the 
valve,  and  also  in  having  a  distinct  posterior  ear,  separated  from  the  body 
of  the  valve  by  an  auricular  furrow.  It  also  resembles  an  example  of  /. 
striatus  Mantell,  in  the  cabinet  of  the  Smithsonian  Institution,  from  Saxony, 
but  the  beaks  of  our  species  are  more  elevated  and  turned  more  forward 
than  they  are  in  that  species.  I.  striatus  is  also  without  the  shallow  radiat- 
ing furrow  before  mentioned.  It  differs  from  I.  flaccidus  White  in  its  smaller 
size,  its  smoother  surface  and  more  gibbous  valves,  that  species  being  coarsely 
and  extravagantly  wrinkled.  Specific  name  given  in  honor  of  Mr.  E.  E. 
Howell,  who  discovered  it  while  geologist  of  one  of  the  surveying  parties. 

Position  and  locality. — Henry's  Fork  Group;  Lower  Potato  Valley  and 
Upper  Pine  Creek,  Utah. 

Genus  AVIOULA  Klein. 

Avicida  Parkensis  (sp.  nov.). — Shell  small,  slightly  inequivalve,  very 
oblique,  elongate,  thin  at  all  the  margins  except  the  cardinal;  anterior  wing 
of  ordinary  size  and  shape;  posterior  wing  rather  large  arid  long;  both 
valves  broadly  but  regularly  convex;  body  of  the  shell  broadest  behind  the 
middle;  antero-basal  border  broadly  convex;  posterior  extremity  regularly 
rounded;  postero-dorsal  border  nearly  straight  from  the  posterior  border  to 
the  base  of  the  posterior  wing;  beaks  of  ordinary  prominence;  surface  ap- 
parently smooth. 

Length  from  the  end  of  the  anterior  wing  to  the  posterior  extremity  of 
the  shell,  thirty-four  millimeters;  breadth  across  the  widest  part  of  the  body, 
fifteen  millimeters. 

This  species  resembles  A.  lingulifera  Shumard,  but  differs  from  that 
species  in  its  more  elongate  form  and  more  oblique  hinge  line. 

Position  and  locality, — Cretaceous  strata;  south  of  Grand  River,  Middle 
Park,  Colorado. 

Genus  ARCA  Linna3us. 

Area?  Coalvillensis  (sp.nov.). — Shell  longer  than  high,  moderately  thick; 
test  somewhat  massive;  beaks  depressed,  situated  near  the  anterior  end; 


116  INVERTEBRATE   PALEONTOLOGY.  [WHITR. 

umbones  broad;  anterior  end  rounded  or  subtrimcate;  base  nearly  straight 
or  very  broadly  convex,  and  often  slightly  emarginate  about  the  middle; 
postero-basal  border  rounded  upward  to  the  posterior  extremity,  which  is 
abruptly  rounded  to  the  downward  sloping,  nearly  straight  postero-dorsal 
border,  the  latter  forming  an  obtuse  angle  with  the  hinge  border;  hinge 
equal  in  height  to  about  two-thirds  the  entire  length  of  the  shell. 

A  slight  depression  or  flattening  extends  from  the  umbo  of  each  valve 
to  its  base,  causing  the  straightening  or  slight  emargination  of  the  basal 
border  before  mentioned.  Area  nearly  obsolete ;  hinge  rather  slender;  two 
or  three  long,  slender  transverse  teeth  occupy  its  middle  portion;  seven  or 
eight  teeth  cross  the  surface  of  its  posterior  end  obliquely  downward  and 
inward,  and  about  an  equal  number  of  smaller  ones  cross  the  anterior  end 
almost  vertically;  the  inner  ones  of  the  latter  set  of  teeth  being  very  small 
and  situated  nearly  beneath  the  beaks. 

Surface  marked  by  ordinary  lines  of  growth,  and  by  fine  radiating 
lines,  which  are  often  obscure.  Length,  five  centimeters;  height,  thirty- 
three  millimeters. 

Position  and  locality. — Salt  Wells  Group;  Coalville,  Utah 

Genus  UNIO  Retzius. 

Unio  yonionotus  (sp.  nov.). — Shell  elongate-subelliptical  in  marginal  out- 
line; flattened  and  thin  when  young,  but  becoming  gibbous  or  almost  cylin- 
drical with  age;  dorsal  margin  broadly  convex;  base  nearly  straight;  front 
regularly  rounded;  the  rounding  of  the  posterior  end  somewhat  irregular, 
in  consequence  of  the  plications  of  the  valves  at  that  part;  beaks  obsolete, 
the  umbonal  region  of  each  valve  so  flattened  that  they  form  an  acute  angle 
at  the  dorsum  in  the  young,  the  angle  increasing  with  age,  so  that  it  is  very 
obtuse  in  the  adult  shell. 

Surface  of  the  anterior  portion  of  the  shell  marked  by  only  the  ordi- 
nary lines  and  lamellations  of  growth,  but  the  posterior  portion,  comprising 
more  than  half  the  length,  is  marked  by  strong,  more  or  less  irregularly 
radiating  plications,  which  begin  faintly  a  little  forward  of  the  middle,  and 
increase  gradually  in  strength  to  the  posterior  and  postero-basal  margins, 
and  increase  in  number  by  a  few  bifurcations  toward  those  margins;  curv- 


DESCRIPTIONS  OF  NEW  SPECIES. 

ing  upward  and  backward  from  the  uppermost  of  the  longer  plications  there 
are  several  smaller,  short  ones  that  end  at  the  postero-dorsal  margin. 

Length  of  the  largest  example  in  the  collection,  sixty -three  millimeters; 
height,  thirty-five  millimeters.  Young  examples  have  very  different  propor- 
tions, as  well  as  a  marginal  outline  of  different  shape. 

This  species  differs  conspicuously  from  any  other  fossil  Unio  known  to 
me,  although  young  examples  of  it  have  some  resemblance  to  those  of  the 
recent  species  U.  multiplicatus,  but  the  adult  specimens  have  a  very  different 
•aspect.  It  differs  from  U:  belliplicatus  Meek,  from  equivalent  strata  in  South- 
western Wyoming,  in  its  general  shape  and  in  the  position  and  distribution 
of  the  plications,  they  being  most  conspicuous  on  the  anterior  portion  of 
that  shell,  while  the  corresponding  portion  of  ours  is  plain. 

Position  and  locality. — Point  of  Rocks  Group;   Upper  Kanab,  Utah. 

Genus  CYRENA  Lamarck. 
Subgenus  VELOKITINA  Meek. 

Cyrena  (Vdoritina)  erecta  (sp.  nov.). — Shell  of  medium  size,  subovate 
in  marginal  outline  when  adult,  but  subcircular  when  young,  gibbous,  espe- 
cially the  upper  median  portion,  but  somewhat  compressed  laterally  at  the 
postero-basal  portion;  front  and  basal  margins  regularly  and  continuously 
rounded;  postero-basal  extremity  somewhat  abruptly  rounded  upward  to 
the  sloping,  broadly  rounded  postero-dorsal  margin;  umbones  elevated; 
beaks  small,  incurved,  and  pointing  forward;  postero-dorsal  margin  of  each 
valve  flexed  strongly  inward,  so  that  the  hinge-ligament  is  hidden  from 
sight  by  side  view  of  the  shell. 

Surface  marked  by  the  ordinary  lines  of  growth. 

Length,  thirty  millimeters;  height  from  base  to  umbones,  thirty-four 
millimeters. 

Position  and  locality. — Salt  Wells  Group;  Upper  Kanab,  Utah,  and  Ilil- 
liard  Station,  Wyoming. 

Genus  TURNUS  Gabb. 

Turnus  sphenoideus  (sp.  nov.). — Shell  elongate-cuneate,  inflated  in  front, 
narrowed,  and  laterally  flattened  behind;  beaks  anterior,  incurved,  adjacent; 


118  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

postero- dorsal  margin  sloping  from  behind  the  beaks  to  the  posterior  ex- 
tremity, and  apparently  capped  by  a  slender,  accessory  plate;  posterior 
extremity  abruptly  rounded;  basal  margin  nearly  straight;  front  regularly 
rounded,  both  laterally  and  vertically;  anterior  gape  consisting  of  a  narrow, 
vertical  slit  that  occupies  the  middle  of  a  somewhat  prominent  projection  at 
the  antero-basal  portion  of  the  shell,  which  projection  has  the  shape  of  a 
Norman  shield,  as  seen  by  front  view,  when  both  valves  are  in  their  natural 
position  i  umbonal  groove  distinct  and  moderately  deep,  causing  a  distinct 
groove  upon  the  stony  internal  casts  of  the  shell,  which  is  of  about  the' 
same  dimensions  and  character  as  that  which  is  left  by  the  radiating  internal 
rib ;  besides  these  two  grooves,  there  is  another,  somewhat  broader  furrow 
radiating  from  behind  the  beak  of  each  valve  to  near  the  posterior  end.  A 
broad,  cake-like  accessory  plate  covers  the  beaks  and  the  space  between 
them;  and,  apparently,  two  others,  one  upon  each  valve,  occupy  the  space 
between  the  umbonal  plates  and  the  top  of  the  Norman  shield-shaped  pro- 
jection before  mentioned. 

Surface  marked  by  fine,  concentric,  raised  lines,  besides  the  radiating 
furrows  before  mentioned.  The  masses  of  rock  from  which  our  specimens 
were  broken  out,  contained  what  appear  to  have  been  calcareous,  siphonal 
tubes,  but  none  of  them  were  found  to  be  unmistakably  connected  with  the 
shells. 

Length,  thirteen  millimeters ;  greatest  height,  seven  millimeters ;  breadth 
at  the  front,  six  millimeters. 

Position  and  locality. — Sulphur  Creek  Group;  Upper  Kanab,  Utah. 

Gasteropoda. 

Genus  RHYTOPHORUS  Meek. 

Rliytoplionis  Mcckii  (sp.  nov.). — Shell  subfusiform;  spire  moderately  pro- 
duced, nearly  one-third  as  long  as  the  entire  length  of  the  shell ;  volutions 
about  six,  convex,  the  last  one  somewhat  large,  elongate,  convex,  and  taper- 
ing from  the  middle  toward  the  anterior  end ;  suture  impressed,  and  upon 
the  proximal  side  of  it  there  is  an  almost  equally  impressed  revolving  line, 
having  the  aspect  of  a  second  suture ;  folds  of  the  eolumella  well  developed. 

Surface  marked  by  the  ordinary  lines  of  growth   and  also   upon   the 


DESCRIPTIONS  OF  NEW  SPECIES.  H9 

spire  by  numerous  small  longitudinal  folds,  parallel  with  the  slightly 
oblique  direction  of  the  lines  of  growth.  These  folds  appear  upon  the  distal 
portion  only  of  the  last  volution. 

Length  of  the  largest  example  obtained,  twenty-five  millimeters;  diam- 
eter of  the  body  volution,  twelve  millimeters. 

This  species  differs  from  R.  priscus  Meek,  with  which  it  is  associated 
in  the  less  robust  and  more  elongate  form  of  the  shell,  its  proportionally 
longer  spire,  niore  delicate  and  finer  markings,  and  the  less  abrupt  convexity 
of  the  volutions  upon  the  proximal  side  of  the  suture. 

The  specific  name  is  given  in  honor  of  the  author  of  the  genus. 

Position  and  locality. — Point  of  Rocks  Group ;  Bear  River  Valley,  near 
Mellis  Station,  Wyoming. 

Genus  PLANORBIS  Guettard. 
Subgenus  BATHYOMPHALUS  Agassiz. 

Planorlls  (BatUyomplialus)  Kanabensis  (sp.  nov.). — Shell  rather  small ; 
spire  flat  or  nearly  so,  suture  impressed ;  volutions  five  or  six,  narrow, 
regularly  increasing  in  size  to  the  aperture,  broadly  convex  upon  the  upper 
side ;  periphery  abrubtly  rounded  to  the  broadly  convex  under  side,  the 
latter  extending  obliquely  downward  and  inward  to  the  well  defined,  mod- 
erately broad,  and  deep  umbilicus. 

Surface  marked  by  ordinary  lines  of  growth. 

Diameter  of  coil,  twelve  millimeters. 

Position  and  locality. — Point  of  Rocks  Group;   Upper  Kanab,  Utah. 

Genus  PHYSA  Draparnaud. 

PJiysa  Kanabensis  (sp.  nov.). — Shell  rather  under  the  average  size;  very 
elongate ;  spire  extended ;  volutions  about  six,  broadly  convex ;  aperture 
very  narrow,  ending  sharply  at  its  distal  end  and  abruptly  rounded  at  the 
proximal  end. 

The  specimens  of  the  collection  are  all  imperfect,  but  the  species  is 
peculiarly  distinguished  by  its  very  slender  elongate  form,  its  extended  spire, 
spire,  and  its  very  narrow  elongate  aperture. 

Position  and  locality. — Point  of  Rocks  Group ;  Upper  Kanab,  Utah. 


120  INVERTEBRATE   PALEONTOLOGY.  [WHITE. 

Genus  HELIX  Linnaeus. 

Helix  Kanabensis  (sp.  nov.). — Shell  having  the  general  external  shape 
and  character  of  H.  palliata  Say,  but,  besides  being  considerably  smaller,  it 
presents  some  differences  in  its  aperture.  Like  that  species,  its  lip  is  re- 
flexed,  and  it  has  a  similar  large  tooth  upon  its  parietal  wall.  In  addition 
to  the  latter  there  are  four  short  linear  ridges  upon  the  inner  surface  just 
within  the  upper  and  outer  portion  of  the  aperture,  at  the  margin  of  which 
they  terminate  exteriorly,  but  extend  inward  in  the  direction  of  the  whorl 
from  two  to  three  millimeters.  The  lowermost  of  these  small  ridges  is 
shortest,  but  more  prominent  and  tooth-like  than  the  others.  Only  a  single 
specimen  was  obtained,  and  that  is  very  imperfect.  It  is  described  and 
named  here  because  of  its  value  as  showing  the  great  differentiation  of 
Helecine  types  30  early  AS  the  Cretaceous  period. 

Position  and  locality. — Point  of  Rocks  Group;   Upper  Kanab,  Utah. 

Genus  ANCHURA  Conrad. 

Anclmra  ruida  (sp.  nov.). — Shell  rather  small ;  spire  moderately  elon- 
gate ;  volutions  about  seven,  convex ;  suture  impressed ;  wing  moderately 
large,  contorted,  bearing  at  its  extero-posterior  corner  a  falciform  process 
which  points  backward  in  the  direction  of  the  spire ;  the  outer  border  of 
this  process  and  also  that  of  the  body  of  the  wing  continuously  and  broadly 
rounded  to  the  extero-anterior  corner  of  the  wing,  which  is  abruptly 
rounded ;  thence  the  anterior  border  of  the  wing  extends  nearly  straight 
inward  to  a  somewhat  broad  curved  sinus  adjacent  to  the  columella,  which 
sinus  corresponds  to  the  anterior  canal  in  other  species;  inner  border  of  the 
falciform  process  broadly  concave  ;  and  between  that  process  and  the  spire 
the  distal  border  of  the  wing  is  shortly  concave  and  a  little  reflexed,  sug- 
gestive of  a  broad  posterior  canal,  especially  as  the  anterror  canal  is  more 
than  usually  broad;  inner  lip  provided  with  a  distinct  callus,  which  in  some 
cases  at  least  extends  beyond  the  distal  end  of  the  aperture  across  the  next 
volution ;  columella  not  much  produced  in  front ;  volutions  of  the  spire 
marked  by  many  longitudinally  oblique  folds,  which  extend  to  the  suture 
on  the  proximal  side  of  the  volutions,  but  not  much  beyond  the  middle  on 
the  distal  side,  and  do  not  appear  at  all  on  the  body  volution  or  wing. 


DESCRIPTIONS  OF  NEW  SPECIES.  121 

The  whole  surface  marked  by  fine  revolving  striae,  which  are  more 
distinct  upon  the  last  volution  and  wing ;  last  volution  also  marked  by  a 
moderately  strong  revolving  carina,  which  extends  outward  upon  the  wing 
and  is  continued  to  the  point  of  the  falciform  process. 

Length,  sixteen  millimeters;  breadth  across  the  body  volution,  includ- 
ing the  wing,  twelve  millimeters. 

This  species  resembles  A.  Americana  Meek  and  Hay  den.  in  general 
form  and  surface  markings,  but  it  differs  from  that  shell  by  its  large  anterior 
sinus,  the  inflection  of  the  anterior  border,  and  the  reflexion  of  the  posterior 
border  of  the  wing,  and  also  in  the  general  shape  of  the  wing. 

Position  and  locality. — Sulphur  Creek  Group;  Upper  Kanab,  Utah. 

Ancliura  prolabiata  (sp.  nov.). — Shell  rather  above  medium  size,  sub- 
fusiform  ;  spire  elongated  and  tapering,  with  nearly  straight  sides,  to  a 
point ;  volutions,  nine  or  ten,  convex,  the  last  one  proportionally  more  en- 
larged than  the  others ;  suture  impressed ;  wing  large,  broad,  its  outer 
border  nearly  straight  or  slightly  convex,  its  anterior  and  posterior  corners 
abruptly  rounded ;  posterior  border  bearing  a  strong,  broad,  blunt  process 
about  midway  between  the  spire  and  the  outer  margin  of  the  wing,  the 
outer  margin  of  the  process  having  a  direction  parallel  with  that  of  the 
outer  margin  of  the  wing ;  posterior  border  of  the  wing  concave  between 
the  outer  corner  and  the  base  of  the  process,  and  also  regularly  and  con- 
tinuously concave  from  the  spire  to  the  end  of  the  process  ;  anterior  border 
of  the  wing  broadly  and  regularly  concave  to  the  base  of  the  anterior  canal, 
which  is  apparently  rather  short. 

Inner  lip  unknown. 

Surface  of  the  volutions  of  the  spire  marked  by  numerous  vertical  or 
slightly  oblique  folds  or  ridges,  which  disappear  upon  the  body  volution 
and  wing ;  these  folds  are  crossed  by  numerous  fine  revolving  raised  lines, 
which  are  hardly  visible  without  the  aid  of  a  lens,  except  those  adjacent  to 
the  sutures,  which  are  stronger ;  these  revolving  lines  are  perceptible  upon 
the  body  volution,  but  are  very  faint  upon  the  wing.  No  revolving  ridge 
passes  out  upon  the  wing  from  the  body  volution,  such  as  is  common  upon 
shells  of  this  genus. 

Length  about  four  and  a  half  centimeters ;  breadth,  measured  across 


122  INVERTEBRATE   PALEONTOLOGY.  [WHITE. 

the  wing  and  body  volution,  twenty-nine  millimeters;  diameter  of  the  body 
volution,  fifteen  millimeters. 

This  species  differs  from  all  others  known  to  me  by  the  projection  of. 
the  outer  border  of  the  wing  beyond  the  posterior  process. 

Position  and  locality. — Sulphur  Creek  Group;   Upper  Kanab  and  Sink 

Spring,  Utah. 

Genus  LUNATIA  Gray. 

Lunatia  Utahensis  (sp.  nov.). — Shell  globose ;  spire  small,  acute,  but 
not  much  extended ;  volutions  about  eight,  the  last  one  much  inflated, 
suture  moderately  impressed ;  aperture  semilunar,  somewhat  abruptly 
rounded  anteriorly,  callus  of  the  inner  lip  apparently  not  much  thickened, 
but  thicker  anteriorly  than  posteriorly.  Surface  marked  by  the  ordinary 
lines  of  growth. 

Length  from  the  apex  to  the  anterior  end  of  the  aperture  about  four 
centimeters;  diameter  about  three  centimeters. 

Position  and  locality. — Salt  Wells  Group;  Coalville,  Utah. 

Genus  GONIOBASIS  Lea. 

Goniobasis  Clelurni  (sp.  nov.). — Shell  large,  gradually  tapering  from  the 
last  volution  to  the  apex,  the  sides  of  the  spire  being  only  slightly  convex; 
volutions  apparently  nine  or  ten,  gradually  increasing  in  size,  .the  last  one 
not  being  proportionally  larger  than  the  others;  suture  slightly  impressed; 
sides  of  the  volutions  nearly  flat  or  slightly  convex,  the  outer  and  anterior 
sides  of  the  last  one  broadly  and  regularly  convex;  aperture  ovate;  outer 
lip  broadly  sinuate. 

Surface  of  the  spire  marked  by  strong  longitudinal  or  slightly  flexed  and 
oblique  ridges  or  folds  which  disappear  toward  the  aperture  of  the  last  volu- 
tion. Upon  the  anterior  surface  of  the  last  volution  beyond  the  distal  end 
of  the  aperture,  there  are  several  slightly  raised  revolving  lines,  and  the 
edges  of  the  vertical  plications  are  also  sometimes  seen  to  be  faintly  crerm- 
lated  as  if  by  incipient  revolving  lines. 

The  specimens  of  the  collection  have  all  lost  the  apex,  but  the  length 
of  a  full  grown  one  is  estimated  at  five  centimeters;  diameter  of  the  last 
volution,  nineteen  millimeters. 


DESCRIPTIONS  OF  NEW  SPECIES.  123 

This  is  the  largest  species  of  Goniobasis  known  to  occur  at  the  locality 
where  it  was  found,  and  which  has  furnished  three  other  distinct  species. 

The  specific  name  is  given  in  honor  of  Mr.  W.  Cleburn,  division  en- 
gineer of  the  Union  Pacific  Railroad. 

Position  and  locality. — Point  of  Rocks  Group;  Bear  River  Valley,  near 
Mellis  Station,  Wyoming. 

Goniobasis  clirysaloidea  (sp.  no  v.).— Shell  of  medium  size,  gradually  taper- 
ing from  the  last  volution  to  the  apex;  volutions  about  seven  or  eight,  those 
of  the  spire  slightly  convex,  the  last  one  broadly  rounded  to  the  anterior 
end;  suture  impressed,  the  apparent  impression  being  increased  by  the  pro- 
jecting fold  of  the  distal  edge  of  each  volution,  which  is  appressed  against 
the  proximal  edge  of  the  next  preceding  one. 

Surface  marked  by  more  or  less  distinct  longitudinal,  slightly  bent  folds, 
which  are  crossed  by  several  revolving  lines  that  appear  only  upon  the  folds 
and  not  between  them,  giving  them  a  knotted  or  crenulated  appearance; 
anterior  surface  of  the  last  \olution  also  marked  by  distinct  raised  revolving 
lines. 

Length  twenty-eight  millimeters;  diameter  of  the  last  volution,  nine 

O  */  o 

millimeters. 

This  species  differs  from  G.  chrysalis  Meek  in  its  much  larger  size, 
much  greater  apical  angle,  straighter  sides,  and  in  the  details  of  its  ornamen- 
tation. 

Position  and  locality.— Point  of  Rocks  Group;  Bear  River  Valley,  near 
Mellis  Station,  Wyoming. 

Genus  VIVIPARUS  Montfort, 

Viviparus  Pangmtchensis  (sp.  nov.). — Shell  elongate-trochiform ;  spire 
considerably  produced  in  the  case  of  some  of  the  examples,  but  less  so  in 
others,  convex-conical,  diminishing  more  rapidly  near  the  apex  than  at  the 
proximal  half  of  the  shell ;  apex  acute ;  volutions  about  six,  flattened  upon 
the  outer  side,  especially  the  last  two  volutions;  anterior  side  of  the  last 
volution  broadly  rounded  and  forming  a  more  or  less  distinct  angle  with  the 
outer  side;  the  distal  side  of  each  volution  concave  to  receive  the  convex 


124  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

proximal  side  of  the  next  preceding  one,  but  projects  a  little  beyond  it  so 
that  an  angular  shoulder  is  formed  upon  the  proximal  side  of  the  suture. 

Aperture  subtrihedral  in  outline. 

Surface  marked  by  the  ordinary  lines  of  growth,  arid  also  by  numerous 
minute,  raised  revolving  striae,  upon  both  the  outer  and  anterior  sides  of 
the  volutions. 

There  is  considerable  variation  in  the  flattening  of  the  outer  side  of  the 
volutions  in  different  examples  and  in  different  parts  of  the  same  example. 
The  volutions  near  the  apex  of  all  the  shells  are  usually  convex  and  not 
much  if  at  all  flattened ;  in  some  cases  the  outer  side  of  the  last  volution  is 
broadly  convex,  while  in  others  it  is  not  only  flattened-  but  a  little  concave, 
especially  the  part  nearest  the  suture. 

Length  of  an  average  sized  example,  thirty  millimeters;  diameter  of 
the  last  volution,  twenty  millimeters. 

Genus  ODONTOBASIS  Meek. 

Odontobasis  buccinoidea  (sp.  nov.). — Shell  of  medium  size  somewhat 
robust;  volutions  six  or  seven,  regularly  convex;  suture  faintly  impressed; 
surface  marked  by  somewhat  strong  longitudinal  folds  which  end  at  the 
suture  upon  the  proximal  side  of  the  volutions  of  the  spire,  but  do  not  quite 
reach  the  suture  upon  the  distal  side,  and  upon  the  last  volution  they  die 
out  before  reaching  the  anterior  end  of  the  shell;  the  whole  surface  also 
marked  by  somewhat  coarse  revolving  raised  lines,  which  in  crossing  the 
longitudinal  folds  give  them  a  crenulated  appearance.  The  revolving  lines 
upon  a  narrow  space  on  the  proximal  side  of  the  suture,  and  also  upon  the 
space  in  front  of  the  revolving  furrow  of  the  columella,  are  finer  than  the 
others.  Odontoid  process  not  very  prominent,  forming  a  small  angular  pro- 
jection at  the  end  of  the  revolving  furrow  of  the  columella. 

Length,  thirty-seven  millimeters ;  diameter  of  the  last  volution,  twenty- 
two  millimeters;  but  these  proportions  vary  considerably  in  different  shells 
of  the  species. 

Position  and  locality. — Point  of  Rocks  Group;  two  miles  west  of  Point  of 
Rocks,  Wyoming. 


DESCRIPTIONS  OF  NEW  SPECIES.  125 

TERTIARY  PERIOD. 
Mollusca. 

Conchifera. 

Genus  UNIO  Retzius. 

Uniopetrinus  (sp.  nov.). — Shell  very  large,  transversely  elongate,  moder- 
ately thick;  test  massive;  basal  and  dorsal  margins  subparallel;  the  latter 
broadly  but  slightly  convex  and  the  former  nearly  straight  or  faintly  emargi- 
nate  about,  or  a  little  behind  the  middle;  front  abruptly  rounded;  postero- 
dorsal  and  postero-basal  margins,  somewhat  abruptly  rounded  to  the  pos- 
terior margin,  giving,  in  some  cases,  a  subtruncate  appearance  to  the  posterior 
end  of  the  shell;  beaks  depressed,  situated  near  the  anterior  end;  umbones 
broad;  hinge  massive,  both  cardinal  and  lateral  teeth  being  very  strong. 

Surface  apparently  marked  in  no  other  manner  than  by  the  ordinary 
lines  and  imbrications  of  growth.  The  outer  prismatic  layer  is  well  preserved, 
and  the  umbones,  like  those  of  all  the  species  of  Unio  I  have  examined,  from 
the  Mesozoic  and  Cenozoic  strata  of  that  region,  appear  to  have  suffered, 
while  living,  no  erosion,  such  as  is  common  in  the  case  of  the  recent  Unio- 
nidae  of  the  Mississippi  and  its  tributaries. 

Length  of  the  largest  example  in  the  collection,  fifteen  centimeters ; 
height  of  the  same,  seven  and  a  half  centimeters.  In  the  case  of  young 
examples  the  length  is  proportionally  greater. 

This  species  may  be  readily  distinguished  from  all  others  at  all  likely 
to  be  confounded  with  it  by  its  great  size,  elongate  form,  and  its  subparallel 
dorsal  and  ventral  margins. 

Position  and  locality. — Bitter  Creek  Group;   Black  Buttes,  Wyoming. 

Unio  proplieticus  (sp.  nov.). — Shell  small  or  of  medium  size,  obliquely 
subovate  in  marginal  outline,  moderately  thick,  the  greatest  thickness  being 
a  little  below  the  umbones;  test  rather  thick;  umbones  prominent,  directed 
forward;  beaks  curved  inward  and  forward,  reaching  as  far  as,  or  a  little 
farther  than,  the  front  of  the  shell;  front  broad,  nearly  perpendicular;  front 
margin  slightly  convex  above,  but  abruptly  rounded  to  the  basal  margin 
below ;  basal  margin  broadly  rounded,  or  sometimes  a  little  straightened  at 


126  INVERTEBRATE  PALEONTOLOGY.  [WIIITR. 

the  middle;  posterior  extremity  abruptly  rounded;  dorsal  margin  broadly 
rounded  obliquely  downward  to  the  posterior  extremity ;  the  dorsum  of  each 
valve  elevated  and  its  margin  flexed  inward  and  downward  to  the  cardinal 
ligament,  so  that  the  latter  is  hidden  from  sight  by  side  view  of  the  shell. 

Surface  marked  by  the  ordinary  lines  of  growth  and  by  numerous  fine 
radiating  striae,  which  appear  also  in  the  substance  of  exfoliated  portions  of 
the  test 

Length,  five  centimeters;  height  from  -base  to  umbones,  thirty-seven 
millimeters. 

This  species  is  of  the  type  of  U.  clavus  Lamarck,  which  it  much  resem- 
bles in  general  aspect.  It  is  so  different  from  any  other  known  species  of 
Unio  in  the  Tertiary  rocks  of  America  that  it  cannot  be  mistaken  for  any 
of  them. 

Position  and  locality. — Bitter  Creek  Group;  Black  Buttes,  Wyoming. 

Unio  bracliyopistlms  (sp.  nov.). — Shell  small  or  of  medium  size,  some- 
what gibbous,  subcircular  in  marginal  outline,  the  length  and  height  being 
about  equal ;  umbones  broad,  not  prominent ;  beaks  depressed,  situated 
near  the  middle  of  the  dorsum ;  postero-dorsal  portion  broad,  depressed  so 
that  rounded  timbonal  ridges  are  formed,  which  extend  to  the  postero-basal 
extremity,  and  the  hinge  ligament  is  hidden  from  sight  by  side  view  of  the 
shell. 

Surface  marked  only  by  the  ordinary  lines  and  lamellations  of  growth. 

Length  and  height  of  the  largest  example  discovered,  each  forty-four 
millimeters. 

This  species  may  be  readily  distinguished  from  all  others  by  its  sub- 
circular,  marginal  outline  and  its  extremely  short  and  abruptly-rounded 
posterior.  The  shortness  of  the  posterior  portion  does  not  appear  so  con- 
spicuously in  the  young  shell  as  in  the  adult,  because  the  additions  by 
growth  are  made  more  rapidly  upon  the  basal  and  antero-basal  borders 
than  elsewhere. 

Position  and  locality.— Bitter  Creek  Group ;  Black  Buttes,  Wyoming. 

Unio  Slioslionensis*  (sp.  nov.). — Shell  of  ordinary  size,  broadly  subel- 

*  The  so-called  tribal  name  is  applied  by  the  Indians  themselves  to  their  country  or  laud,  riot  to 
the  tribe. 


DESCRIPTIONS  OF  NEW  SPECIES.  127 

Hptical  or  subovate  in  marginal  outline  ;  valves  moderately  and  somewhat 
regularly  convex ;  test  not  massive.;  dorsal  margin  broadly  arched ;  front 
margin  regularly  rounded ;  basal  margin  broadly  and  regularly  rounded ; 
posterior  margin  somewhat  abruptly  rounded,  the  postero-dorsal  portion 
sometimes  obliquely  truncated  and  sometimes  sloping  to  a  more  prominent 
posterior  extremity;  beaks  well  denned,  but  not  prominent;  umbones 
broadly  convex. 

Surface  marked  by  the  ordinary  lines  and  lamellations  of  growth. 

Length  of  the  largest  example  in  the  collection,  nearly  seven  centi- 
meters ;  height  of  the  same,  five  centimeters. 

This  species  bears  some  resemblance  to  U.  Haydeni  Meek,  from  the 
Bridger  Group,  but  differs  from  that  species  in  its  larger  size,  its  convex 
instead  of  straight  dorsal  margin,  its  rather  more  prominent  umbones,  and 
its  greater  propor donate  height. 

Position  and  locality. — Upper  Green  River  Group;  Henry's  Fork  and 
Alkali  Stage  Station,  Wyoming ;  also  in  Lower  Green  River  Group ;  west 
side  of  Snake  River,  six  miles  north  of  Junction  Mountain ;  Cliffs,  four 
miles  northeastward  from  Vermilion  Canon ;  and  Dry  Mountains,  North- 
western Colorado. 

Genus  CORBICULA  Miihlfeldt. 

Corbicula  Powelli  (sp.  nov.). — Shell  rather  small,  subelliptical  in  mar- 
ginal outline  ;  valves  thin,  slightly  but  somewhat  uniformly  convex ;  beaks 
small,  not  prominent ;  cardinal  and  lateral  teeth  well  developed ;  both 
anterior  and  posterior  lateral  teeth  finely  crenulated  transversely ;  middle 
cardinal  tooth  of  each  valve  having  a  shallow  vertical  groove  along  its 
middle ;  a  very  faintly-raised  ridge  extends  downward  from  beneath  the 
beak  on  the  inner  surface  of  each  valve,  and  dies  out  before  reaching 
the  base.  Surface  nearly  smooth,  but  marked  by  fine  lines  of  growth. 

Length,  twenty-three  millimeters ;  height,  from  beak  to  base,  fifteen 
millimeters ;  thickness,  eight  millimeters. 

This  shell  differs  from  typical  forms  of  Corbicula  in  its  elliptical  out- 
line, slight  thickness,  and  in  the  delicacy  of  the  test.  All  the  species 
associated  with  it,  except  an  oyster,  are  exclusively  marine  forms. 


128  INVERTEBRATE   PALEONTOLOGY.  [WHITE. 

Specific  name  given  in  honor  of  Prof.  J.  W.  Powell,  geologist  in  charge 
of  the  Second  Division  United  States  Geological  and  Geographical  Survey. 

Position  and  locality. — Tertiary  strata,  probably  late  Eocene ;  Bijou 
Basin,  forty  miles  east  of  Denver,  Colorado. 

Genus  PISIDIUM  Pfeiffer. 

Pisidium  saginatum  (sp.  nov.). — Shell  small,  subcircular  in  marginal 
outline ;  anterior  side  slightly  longer  than  the  posterior ;  valves  inflated, 
the  convexity  from  beak  to  base  being  sometimes  irregular  in  consequence 
of  one  or  more  abrupt  concentric  flexures. 

Surface  marked  by  ordinary  lines  of  growth. 

Length,  five  millimeters ;  height,  five  and  a  half  millimeters ;  thick- 
ness, five  and  a  half  millimeters. 

Position  and  locality. — Bitter  Creek  Group;  Alrny  coal  mines,  near 
Evanston,  Wyoming. 

Genus  MESODESMA  Deshayes. 

MesQdesma  Bishopi  (sp.  nov.). — Shell  small,  subovate  or  subtrihedral  in 
marginal  outline,  moderately  gibbous ;  umbonal  ridges  somewhat  distinct, 
the  posterior  pair  more  so  than  the  others ;  umbones  prominent ;  beaks 
small ;  both  anterior  and  posterior  lateral  teeth  well  developed  and  trans- 
versely striated,  as  in  Corbicula;  cartilage  pit  beneath  the  beak  small;  car- 
dinal tooth  in  front  of  it  rather  small  and  V-shaped;  pallial  sinus  deep; 
muscular  scars  distinct ;  right  valve  unknown. 

Surface  nearly  smooth,  and  marked  by  very  fine  lines  of  growth. 

Length,  about  one  centimeter ;  height,  about  six  millimeters. 

This  shell  differs  from  typical  forms  of  Mesodesma  in  its  V-shaped  car- 
dinal tooth,  transversely  striated  lateral  teeth,  and  deep  pallial  sinus. 

Specific  name  given  in  honor  of  Prof.  F.  M.  Bishop,  of  Salt  Lake  City, 
Utah. 

Position  and  locality. — Tertiary  strata,  probably  late  Eocene ;  Bijou 
Basin,  forty  miles  east  of  Denver,  Colorado. 


DESCRIPTIONS  OF  NEW  SPECIES.  129 

Genus  CORBULA  Bruguiere. 

Corlula  subundifera  (sp.  nov.).— Shell  of  ordinary  size ;  marginal  out- 
line subtrihedral  or  subovate ;  valves  only  slightly  unequal ;  beaks  con- 
tiguous ;  umbones  moderately  prominent ;  beaks  incurved  and  directed  a 
little  forward;  front  obliquely  truncate,  concave,  producing  indistinctly 
defined  anterior  umbonal  ridges ;  abruptly  rounded  below  to  the  basal 
margin,  which  is  broadly  rounded;  posterior  extremity  low,  prominent,  and 
sharply  rounded;  postero-dorsal  margin  sloping  from  the  dorsum  to  the 
posterior  extremity ;  this  margin  of  each  valve  is  bent  abruptly  inward  and 
downward,  producing  a  narrow,  shallow  furrow,  bordered  at  each  side  by  a 
somewhat  prominent  ridge,  which  extends  from  behind  the  beak-  to  the 
posterior  extremity  of  the  shell. 

Surface  marked  by  numerous,  more  or  less  strongly  elevated,  con- 
centric folds,  which  disappear  before  reaching  the  anterior  and  posterior 
margins.  Between  these  folds,  and  upon  those  parts  of  the  surface 
unmarked  by  them,  the  surface  is  marked  by  ordinary  lines  of  growth. 

Length,  twenty-five  millimeters  ;  height,  eighteen  millimeters. 

This  species  closely  resembles  C.  undifer  Meek,  from  the  Point  of  Rocks 
Group  at  Rock  Springs,  Wyoming,  but  differs  from  that  species  in  its  less 
extended  posterior  extremity,  its  less  angular  posterior  umbonal  ridges,  its 
less  sharply  elevated,  concentric  folds,  and  in  wanting  the  peculiar  flattening 
of  the  umbones  between  the  posterior  and  anterior  umbonal  ridges  which 
that  species  possesses. 

Position  and  locality. — Bitter  Creek  Group;  Point  of  Rocks,  Wyoming. 

Gasteropoda. 
Genus  SUCCINEA  Draparnaud. 

Succinea  papillispira  (sp.  nov.). — Shell  rather  small,  ovate  or  subelliptical 
in  lateral  outline;  spire  minute  but  prominent;  last  volution  much  expanded 
and  broadly  convex. 

Surface  marked  by  the  ordinary  lines  of  growth,  and,  under  a  lens, 
faint,  close-set,  revolving  striae  are  to  be  seen. 

Length,  eleven  millimeters;  breadth  of  aperture,  six  millimeters. 

9PG 


INVERTEBRATE  PALEONTOLOGY.  [win™. 

This  species  possesses  peculiar  interest  from  the  fact  that  it  is  the  first 
Sucdnea  that  has  been  discovered  in  the  Tertiary  strata  of  that  great  region. 
Although  there  are  so  few  salient,  specific  characters  in  any  species  of  the 
genus,  this  shell ,  may  be  readily  recognized  by  its  minute  spire,  the  length 
of  which  is  only  a  very  small  part  of  the  full  length  of  the  shell,  and  also 
by  its  broadly  convex  last  volution. 

Position  and  locality. — Upper.  Green  River  Group ;  Alkali  Stage  Station, 
twenty-two  miles  northwward  from  Green  River  Station,  Wyoming. 

Genus  HELIX  Linnaeus. 

Helix  riparia  (sp.  nov.). — Shell  of  medium  size,  subconical;  volutions 
about  five,  moderately  convex;  suture  slightly  impressed;  spire  considerably 
produced  for  a  species  of  this  genus,  equal  in  length  to  about  three-sevenths 
of  the  entire  length  of  the  shell;  proximal  side  of  the  last  volution  broadly 
and  continuously  rounded  from  the  outer  side;  umbilicus  small,  rather  deep; 
outer  lip  unknown;  aperture  oblique,  broadly  subovate  in  outline. 

Surface  marked  by  the  ordinary  distinct  lines  of  growth. 

Position  and  locality. — Lower  Green  River  Group;  eight  miles  below 
Green  River  Station,  Wyoming.  • 

*  Helix  periplieria  (sp.  nov.). — Shell  of  ordinary  size,  sublenticular  in 
form;  spire  low  and  broadly  convex;  volutions  about  five,  each  broadly 
convex  between  the  sutures;  the  last  volution  abruptly,  almost  angularly, 
rounded  at  the  periphery  of  the  shell;  under  side  broadly  convex  and  rounded 
sharply  into  a  small,  deep'  umbilicus.  Lip  apparently  not  reflexed. 

Surface  marked  by  the  ordinary  distinct  lines  of  growth. 

Peripheral  diameter,  about  fifteen  millimeters. 

Position  and  locality. — Bitter  Creek  Group;  south  base  of  Pine  Valley- 
Mountains,  Utah. 

Genus  PUPA  Lamarck. 

Pupa  incolata  (sp.  nov.). — Shell  small,  turreted,  regularly  tapering  to 
the  apex;  volutions  about  six,  convex,  regularly  increasing  in  size  to  the 
aperture,  the  last  one  not  being  contracted;  suture  impressed;  aperture  sub- 
ovate  in  outline,  its  length  a  little  more  than  one-third  that  of  the  whole 
shell;  outer  lip  thickened,  reflexed. 


DESCRIPTIONS  OF  NEW  SPECIES.  131 

Length,  five  millimeters;  diameter  of  last  volution,  two  millimeters. 

This  species  is  of  about  the  same  size  as  the  recent  species  Pupafallax 
Say,  and  closely  resembles  it  in  form  and  general  character. 

Position  and  locality. — Upper  Green  River  Group;  Henry's  Fork,  Wyo- 
ming, where  it  is  associated  with  the  following  species: 

Pupa  arenula  (sp.  nov.). — Shell  minute,  ovate;  volutions  five  or  six,  con- 
vex; suture  impressed;  aperture  contracted;  teeth  of  the  aperture  unknown. 

Length,  two  millimeters. 

This  shell  is  of  about  the  same  size  and  shape  as  Vertigo  ovata  Say,  and 
in  general  aspect  it  closely  resembles  that  species.  It  appears,  however,  to 
be  a  true  pupa;  at  least  the  characters  which  should  separate  it  from  that 
genus  are  not  apparent. 

Position  and  locality. — Upper  Green  River  Group ;  Henry's  Fork,  Wyo- 
ming. 

Genus  NERITINA  Lamarck. 

Nentina  volvilineata  (sp.  nov.). — Shell  small,  subovate  in  lateral  outline; 
volutions  three  and  a  half  or  four,  regularly  convex;  spire  short,  as  is  common 
in  this  genus,  but  somewhat  prominent;  suture  slightly  impressed ;  aperture 
semilunar;  inner  lip  broad,  plain,  flat,  its  inner  edge  not  clearly  seen,  but  if 
crenulated  at  all,  it  is  not  conspicuously  so. 

Surface  marked  by  numerous  raised,  revolving  lines  of  unequal  size, 
which  increase  in  number  by  implantation  as  the  volutions  increase  in  size; 
the  revolving  lines  crossed  by  the  usual  lines  of  growth,  which  give  the 
surface,  upon  some  parts,  at  least,  an  indistinctly  cancellated  appearance 
under  the  lens. 

Greatest  diameter  of  the  largest  example  discovered,  nine  millimeters; 
height,  lying  with  its  aperture  upon  the  table,  five  millimeters. 

Position  and  locality. — Bitter  Creek  Group;  Black  Buttes,  Wyoming. 

Genus  MELANIA  Lamarck. 

Melania  Lanmda  (sp.  nov.). — Shell  large,  elongate;  volutions  apparently 
eleven  or  twelve,  uniformly  increasing  in  size,  moderately  convex,  bearing 
a  revolving  row  of  prominent,  strong,  outward  projecting,  laterally  sharp- 
ened tubercles,  which  extend  from  the  apex  to  the  aperture;  suture  linear; 


132  INVERTEBRATE  PALEONTOLOGY.  [WHITE. 

surface  of  the  volutions  on  the  distal  side  of  the  row  of  tubercles  without 
revolving  striae,  or  having  one  or  two  indistinct  ones;  surface  upon  the  prox- 
imal side  of  the  row  of  tubercles  marked  by  numerous  elevated,  slightly 
waved,  revolving  striae,  which  are  more  distinct  about  midway  of  the  space 
than  elsewhere,  and  are  very  close  together  near  the  columella.  Only  three 
or  four  of  these  striae  appear  upon  the  volutions  of  the  spire,  because  the 
remainder  are  covered  by  each  succeeding  volution.  Aperture  oval  or  sub- 
elliptical;  outer  lip  having  a  broad,  shallow  notch,  the  retreating  angle  of 
which  is  opposite  the  row  of  tubercles,  anterior  portion  moderately  extended 
and  abruptly  rounded  to  the  columella. 

Length,  about  nine  and  a  half  centimeters,  when  entire ;  diameter  of 
the  last  volution,  twenty-two  millimeters. 

This  species  is  more  nearly  like  a  true  Melanla  of  Old  World  type  than 
any  of  the  so-called  Melanians  of  North  America  with  which  I  am  ac- 
quainted. 

Position  and  locality. — Tertiary  strata  ;  Crow  Creek,  Colorado,  where 
it  was  obtained  by  Mr.  W.  Cleburn. 

Genus  HYDROBIA  Hartmaiin. 

Hydrobia  recta  (sp.  nov.). — Shell  small,  very  slender,  sides  of  the  spire 
straight ;  volutions  convex,  apparently  twelve  or  more,  increasing  regularly 
and  uniformly  in  size  from  apex  to  aperture.  Surface  marked  by  the 
ordinary  lines  of  growth. 

Length  of  one  example  in  the  collection,  nine  millimeters  ;  diameter 
of  the  last  volution  of  the  same, .  one  and  a  half  millimeters.  Other  exam- 
ples indicate  a  length  nearly  twice  as  great  as  that  here  given. 

Position  and  locality. — Bitter  Creek  Group  ;  Almy  coal-mines,  near 
Evanston,  Wyoming. 

Hydrolna  Utahensis  (sp.  nov.). — Shell  rather  small,  elongate-conical, 
spire  moderately  produced,  its  sides  straight  or  nearly  so ;  volutions  about 
six,  convex ;  suture  impressed ;  aperture  ovate,  a  little  longer  than  wide,  its 
distal  extremity  slightly  angular,  its  anterior  end  prominent  and  rounded. 
Surface  marked  by  the  ordinary  lines  of  growth. 


DESCRIPTIONS  OF  NEW  SPECIES.  133 

Length,  about  five  millimeters ;  diameter  of  the  last  volution,  nearly 
two  millimeters. 

Position  and  locality. — Bitter  Creek  Group ;  west  base  of  Mu-si-ni-a 
Plateau,  1,000  feet  below  the  summit,  Utah. 

Genus  VIVIPARUS  Montfort. 

Viviparus  plicapressus  (sp.  nov.). — Shell  rather  under  medium  size ; 
spire,  cqnical ;  sides  nearly  straight ;  volutions  about  seven,  convex,  the 
outer  and  anterior  convexity  of  the  last  one  continuous  and  uniform  ;  suture 
impressed.  At  the  distal  side  of  each  volution  there  is  a  small,  more  or  less 
distinct,  revolving  groove  or  furrow,  by  which  that  part  is  folded  and  closely 
appressed  against  the  proximal  side  of  the  adjacent  volution,  the  fold  form- 
ing a  slight  projection  upon  the  proximal  side  of  the  suture.  Surface 
marked  by  the  ordinary  lines  of  growth,  and  upon  some  examples  there 
appears  a  faintly  raised  revolving  line  or  incipient  angulation  near  the 
middle  of  the  outer  side  of  the  volutions. 

Length,  about  twenty-five  millimeters ;  breadth  of  last  volution,  twelve 
millimeters. 

Position  and  locality. — Bitter  Creek  Group ;  Black  Buttes,  Wyoming. 

Genus  LEIOPLAX    Troschel. 

Leioplax  f  tiirricula  (sp.  nov.). — Shell  of  ordinary  size,  elongate  conical ; 
volutions  about  eight,  gradually  increasing  in  size  ;  convex  angular,  the 
angle  being  sharp,  prominent,  and  situated  a  little  in  advance  of  the  middle 
of  the  side  of  the  volutions  of  the  spire ;  suture  slightly  impressed ;  last 
volution  broadly  rounded  from  the  revolving  angle  to  the  umbilicus  ;  umbil- 
icus narrow,  deep  and  marked  within  by  two  or  three  revolving  lines.  Sur- 
face upon  both  sides  of  the  revolving  angle  of  the  volutions  marked  more 
or  less  distinctly  by  two  or  three  revolving  raised  lines. 

Length,  thirty  millimeters ;  diameter  of  last  volution,  fifteen  millime- 
ters. This  shell  has  the  aspect  of  some  forms  of  Goniobasis,  but  the  presence 
of  an  umbilicus  excludes  it  from  that  genus.  It  also  varies  from  the 
typical  forms  of  Leioplax,  but  appears  to  be  more  nearly  related  to  this  than 


134  INVERTEBRATE   PALEONTOLOGY.  [WHITE. 

to  any  other  established  genus  and  is  accordingly  referred  to  it  provision- 
ally. 

Position  and  locality. — Bitter  Creek  Group  ;  Black  Buttes,  Wyoming. 

Genus  TULOTOMA  Haldeman. 

Tulotoma  Thompsoni  (sp.  nov.). — Shell  moderately  large,  having  the 
general  form  of  shells  of  this  genus;  spire  elevated,  its  sides  broadly  convex; 
volutions  six  or  seven,  their  outer  side  flattened  or  only  slightly  ^convex ; 
proximal  side  of  the  last  volution  also  flattened  or  slightly  convex,  produc- 
ing a  more  or  less  prominent  revolving  angle  between  them;  suture  linear 
or  faintly  impressed ;  umbilical  chink  minute  or  wanting.  Surface  of  the 
three  or  four  first  volutions  of  the  spire  convex  and  unmarked,  except  by 
the  ordinary  lines  of  growth,  but  the  last  two  or  three  volutions  are  con- 
spicuously marked  by  prominent  tubercles  in  two  or  three  revolving  rows, 
extending  to  the  aperture,  and  which  sometimes  seem  to  be  connected  in 
their  respective  rows  by  slightly  raised  revolving  lines.  .The  distal  row  of 
tubercles  is  strongest  and  is  situated  near  the  suture,  on  its  proximal  side. 
The  proximal  row  is  immediately  upon  the  distal  side  of  the  suture,  the 
tubercles  of  which  are  more  elongated  transversely  than  the  others,  but  not 
so  prominent.  Between  these  two  rows  there  is  sometimes  another  obscure 
one,  but  upon  some  shells  it  is  reduced  to  only  a  raised  line. 

Length  of  a  large  example,  thirty-eight  millimeters ;  diameter  of  the 
last  volution,  twenty-five  millimeters. 

This  shell  resembles  the  recent  species  T.  magnified  Conrad,  but  differs 
from  that  shell  in  its  more  convex  volutions,  its  faintly  impressed  suture,  and 
the  different  arrangement  of  its  tubercles.  It  also  resembles  T.  (  Viviparits} 
Strossmayeriana  Pilar,  as  published  by  Brasilia,  but  differs  in  the  less  con- 
vexity of  its  volutions,  especially  the  proximal  side,  and  in  the  different 
character  and  position  of  the  tubercles  that  adorn  its  surface. 

Genus  PHOKUS  Montfort, 

Phorus  exonerates  (sp.  nov.). — Shell  small,  concavo-convex,  the  convexity 
of  the  upper  side  being  slight  and  nearly  uniform  ;  volutions  one  and  a  half 
or  two;  suture  not  distinctly  shown;  surface  apparently  quite  plain  or  marked 


DESCRIPTIONS  OF  NEW  SPECIES.  135 

only  by  lines  of  growth;  without  extraneous  bodies  attached  to  the  periphery; 
aperture  very  oblique  and  very  narrow. 

Diameter  of  the  shell,  thirteen  millimeters. 

Position  and  locality. — Tertiary  strata,  probably  late  Eocene;  Bijou 
Basin,  forty  miles  east  of  Denver,  Colorado. 


OH  A.1? TEH,    IV. 


GEOGRAPHIC  DISTRIBUTION  OF  THE  GEOLOGICAL 
FORMATIONS  IN  THE  UINTA  MOUNTAINS 

AND  A  DISTRICT  OF  COUNTRY  ADJACENT  THERETO. 

I  propose  to  give  a  brief  description  of  the  geology  of  a  part  of  the 
Uinta  Mountains  and  a  district  of  country  lying  to  the  north,  stretching 
beyond  the  Union  Pacific  Railroad.  The  region  is  embraced  within  the 
meridians  of  108°  30'  and  109°  527.5  west  longitude,  and  between  the  par- 
allels of  40°  15'  and  41°  40'  north  latitude.  The  Green  River  runs  through 
the  middle  of  the  district,  having  a  general  northerly  and  southerly  course, 
but  from  which  it  deflects  in  great  curves. 

The  Uinta  Mountains  are  composed  of  elevated  valleys,  tables,  and 
peaks,  the  latter  having  a  very  irregular  distribution,  due  to  geological 
structure.  The  axis  of  the  range  is  the  axis  of  a  great  flexure,  having  a 
total  displacement  (or  exhibiting  an  upheaval)  of  more  than  30,000  feet, 
This  flexure  terminates  on  the  east  in  the  little  valley  separating  the  Uinta 
Mountains  from  Junction  Mountain.  The  latter  represents  a  short,  abrupt, 
anticlinal  flexure,  having  a  north  and  south  axis  The  Uinta  uplift  lias 
brought  up  all  of  the  Mesozoic  and  Carboniferous  Groups  with  the  Uinta 
Sandstone,  and  in  one  locality  a  still  older  group  of  rocks,  viz,  the  Red 
Creek  Quartzite,  is  exposed.  On  the  flanks  of  the  range,  both  to  the  north 
and  south,  Cenozoic  groups  are  found.  The  grand  Uinta  displacement  is 
only  a  flexure  in  its  general  characteristics,  as  the  down-throw  on  the  north 
side  of  the  axis  is,  in  some  localities,  in  part  produced  by  faulting;  while 
on  the  south  side  of  the  axis  faults  are  found  having  throws  on  the  north 
side  of  the  fissure.  Thus  the  faults,  instead  of  being  a  part  of  the  general 

136 


RED  CHEEK  QUAETZITE.  137 

flexure  of  the  slope,  are  opposed  to  it,  and  the  faults  themselves,  in  a  part 
of  their  courses,  change  to  flexures.  In  addition  to  the  complications  thus 
mentioned,  there  are  other  minor  flexures  within  the  greater.  All  of  these 
complications  will  be  spoken  of  further  on. 

Within  the  district  which  I  undertake  to  describe,  another  great  flexure 
must  be  mentioned.  This  has  a  north  and  south  axis,  and  brings  to  view  in 
the  region  north  of  Aspen  Mountain  the  Sulphur  Creek  Cretaceous.  On 
the  flanks  of  this  flexure  we  find  the  Salt  Wells  and  Point  of  Rocks  Creta- 
ceous, and  the  Bitter  Creek,  Lower  Green  River,  Upper  Green  River  and- 
Bridger  Tertiaries,  all  of  which  groups  took  part  in  the  movement  which 
made  this  flexure ;  but  there  is  no  evidence  that  the  Brown's  Park  Group  or 
the  Bishop  Mountain  Conglomerate  was  involved  in  the  movement.  The 
southern  extremity  of  the  flexure  is  well  seen  at  the  head  of  Red  Creek, 
where  the  rocks  dipping  south  from  the  end  of  the  Aspen  flexure  become 
horizontal,  and  again  are  turned  up  by  the  great  Uinta  flexure,  thus  forming 
a  synclinal  between  the  flank  of  the  greater  flexure  and  the  end  of  the 
lesser.  The  characteristics  of  this  displacement  also  will  be  discussed  here- 
after. 

I  now  proceed  to  describe  the  geographic  distribution  of  the  groups  or 
formations  in  this  district,  and  to  give  their  general  stratigraphic  character- 
istics, and  also  to  note  some  interesting  facts  concerning  their  conformities 
and  unconformities. 

All  of  the  groups  of  rocks  tabulated  in  Chapter  II  are  found  within 
this  area  except  the  Grand  Canon  Group  and  the  Grand  Canon  Schists. 

EED    CHEEK    QUARTZITE. 

The  only  locality  where  this  group  has  been  found  within  the  territory 
embraced  in  the  discussion  is  in  the  vicinity  of  Red  Creek,  a  small  tributary 
of  the  Green  River,  emptying  into  the  latter  at  the  head  or  western  end  of 
Brown's  Park.  Its  geographic  extension  is  well  shown  on  the  map,  and 
needs  no  farther  description. 

Red  Creek  separates  Quartz  Mountain  and  Mount  Wheeler  by  a  tor- 
tuous, flaring,  craggy  canon  whose  sides  rise  to  an  altitude  of  about  "2,000 
feet  above  the  creek,  and  here  the  interior  structure  of  the  group  is  revealed. 


138  GEOGRAPHIC  DISTRIBUTION. 

The  group  embraced  under  the  name  is  the  lowest  horizon  found  within 
the  region  under  discussion.  It  is  composed  in  large  part  of  a  quartzite, 
very  crystalline  and  white,  and  having  the  general  aspect  of  virgin  quartz. 
Only  in  a  few  places  is  the  original  granular  structure  apparent.  Intimately 
associated  with  the  quartzite  are  very  irregular  aggregations  of  hornblendic 
and  micaceous  schists,  the  latter  sometimes  bearing  garnets.  Originally 
these  schists  were  perhaps  argillaceous  strata  between  the  thicker  strata 
of  pure  siliceous  sandstone.  The  whole  group  has  been  greatly  metamor- 
phosed, producing  a  crystallization  that  in  many  places  has  quite,  and  in  the 
remainder  almost,  obliterated  the  original  granular  or  sedimentary  structure, 
so  far  as  it  is  apparent  to  the  naked  eye.  Besides  this  recrystallization  they 
have  been  profoundly  plicated,  or  I  should  rather  say  implicated.  It  is 
only  in  a  general  way  that  any  original  stratification  can  be  observed. 
This  original  structure  can  best  be  seen  when  standing  at  some  distance 
from  the  beds  to  be  studied. 

Its  relation  to  the  Uinta  Sandstone  above  it  is  exhibited  in  the  lower 
end  of  the  canon  of  Red  Creek  and  along  the  escarpment  which  faces 
Brown's  Park  on  the  south  side  of  Mount  Wheeler,  up  the  canon  of  an 
intermittent  stream  four  miles  farther  west,  and  also  up  the  canon  of  Wil- 
low Creek.  Other  facts  relating  to  the  junction  of  the  two  groups  are  seen 
on  the  summit  of  Quartz  Mountain.  These  facts  are  as  follows:  A  part  of 
the  Uinta  Group,  which  is  later  and  higher,  terminates  abruptly  against  the 
quartzite.  The  thickness  of  the  beds  thus  limited  is  about  8,000  feet,  and 
as  the  beds  are  traced  from  the  southward  to  this  plane  of  junction  they 
rapidly  change  from  finer  to  coarser  sediments,  often  appealing  as  conglom- 
erates in  the  vicinity  of  the  quartzite;  but  the  total  thickness  of  the  beds 
is  not  increased  by  the  transition  from  finer  to  coarser  sediments,  though 
particular  beds  may  thicken,  such  thickening  being  compensated  by  the 
thinning  out  or  disappearance  of  others.  In  these  conglomerates  the  coarser 
materials  are  of  quartzite,  hornblendic  rock,  &c.,  similar  to  those  of  the' Red 
Creek  Group,  held  in  a  matrix  of  siliceous,  hornblendic  and  micaceous 
sands,  wrhich  are  quite  ferruginous.  The  position  of  the  quartzite  is  on  the 
flank  of  the  great  Uinta  flexure,  not  its  axis,  and  the  junction  of  the  lower 
two  or  three  thousand  feet  of  the  Uinta  Sandstone  with  the  quartzite  is  not 


EED  CREEK  QUARTZITE. 


139 


seen;  while  from  two  to  three  thousand  feet  of  the  upper  members  of  the 
Uinta  Sandstone  were  deposited  over  the  summit  of  the  quartzite. 

From  these  facts  we  may  safely  infer  that  this  was  a  great  headland  of 
quartzite  standing-  out  in  the  old  Uinta  Sea  from  some  island,  or  perhaps 
from  the  mainland ;  that  it  rose  above  its  waters  as  a  lofty  mountain,  while 
from  two  to  three  thousand  feet  of  these  sandstones,  whose  junction  with 
the  quartzite  is  unseen,  and  while  8,000  feet  of  sandstone  whose  junction  is 
seen,  were  deposited.  Then  this  mountain  headland  was  buried  with  two 
or  three  thousand  feet  of  the  upper  members  of  the  Uinta  Group.  During 
that  great  movement  which  began  during  Cenozoic  time,  and  which  has  con- 
tinued intermittantly  unlil  the  present,  and  which  has  given  us  the  Uinta 
upheaval,  this  quartzite  behaved  in  a  general  way  as  an  integral  part  of  the 
sandstone,  flexing  when  the  sandstone  flexed  and  faulting  when  the  sand- 
stone faulted.  In  the  upper  part  of  Figure  11  we  have  a  diagram  exhibiting 


U.  Uinta  Group.     K.  Red  Creek  Quartzite.     C.  Cretaceous. 

Fig.  11.— Section  and  diagram  of  the  Red  Crock  Unconformity. 

the  relation  of  these  two  groups  as  now  seen ;  the  lower  part  of  the  same 
figure  represents  a  restoration  of  the  same  section  to  the  position  these  two 
groups  held  prior  to  the  inception  of  the  Uinta  upheaval.  It  will  be  seen 
that  the  old  shore  line,  in  vertical  outline,  was  now  a  bold  cliff  against  which 


140  GEOGRAPHIC  DISTRIBUTION. 

the  waves  of  the  Uinta  Sea  dashed,  forming  deep  caverns  in  the  mural  rock, 
and  then  at  other  horizons  was  a  retreating  slope.  A  further  study  of  the 
facts  shows  that  on  a  horizontal  plain  the  projecting  rocks  inclosed  deep  bays. 
But  we  must  remember  that  as  the  beds  were  deposited  denudation  pro- 
gressed ;  so  that  the  slope  seen  does  not  represent  it  as  it  existed  at  any 
one  time  during  the  deposition  of  the  beds,  but  only  the  slope  which  was 
finally  produced.  At  the  beginning  of  the  Uinta  epoch  it  must  have  been 
much  steeper  than  it  is  represented  in  the  diagram. 

About  10,000  feet  of  the  Uinta  Sandstone  is  found  to  have  been  de- 
posited against  the  old  quartzite  headland  before  it  was  buried  by  the  upper 
members  of  the  Uinta  Group.  Hence  this  headland  must  have  been  at 
least  10,000  feet  higii  •  but  doubtless  the  quartzite  itself  was  steadily  de- 

O  '  J 

nucled  during  this  time,  'and  we  may  suppose  that  it  wasted  away  by  erosion 
above  quite  as  rapidly  as  it  was  buried  below.  Certainly  this  supposition 
is  not  violent ;  and  this  would  lead  to  the  conclusion  that  the  great  headland 
was  20,000  feet  high  at  the  time  when  the  lowest  knowji  number  of  the 
Uinta  Sandstone  was  formed.  We  may  now  with  some  degree  of  probability 
resto.re  in  imagination  one  feature  of  that  ancient  geography  and  see  a 
mountain  more  gigantic  in  its  proportions  than  any  which  now  pierces  the 
clouds  floating  over  North  America,  Stand  on  the  great  plain  by  the  Platte 
River  and  look  at  Long's  Peak;  on  it  pile  all  that  can  be  seen  of  Pike's 
Peak  from  the  banks  of  the  Arkansas,  and  over  these  place  all  of  Gray's 
Peak  that  stands  above  the  same  plain,  and  the  mountain  thus  built  up  in 
imagination  would  not  equal  in  altitude  this  quartzite  mountain,  whose  feet 
were  bathed  in  the  old  Unita  Sea.  Geologists  have  arrived  at  the  conclu- 
sion that  these  quartzites  and  schistic  rocks  which  appear  over  man}'  portions 
of  the  earth  were  oriinnallv  accumulated  as  sediments  and  subsequently 

•/  */ 

metamorphosed.  In  the  case  of  this  group  the  metamorphism  was  anterior 
to  the  deposition  of  the  sandstones  as  seen  from  the  facts  mentioned  above, 
viz,  that  the  sandstones  are  composed  of  material  denned  from  the  meta- 
morphic  group.  But  the  sandstones  have  great  thickness  and  underlie  un- 
conformably  an  extensive  series  of  Carboniferous  rocks.  From  this  we  infer 
that  the  quartzite  is  of  great  geological  antiquity. 


DEVELOPMENT  OF  UINTA  SANDSTONE.  141 


UINTA    GROUP. 


As  shown  by  the  map,  the  great  mass  of  the  Uinta  Range  is  composed 
of  sandstones  of  this  group.  Intercalated  with  the  sandstones  some  shales 
are  found,  the  latter  being  arenaceous,  with  a  small  portion  of  argillaceous 
material.  In  a  few  places  the  sandstones  have  assumed  a  crystalline  struc- 
ture, forming  a  quasi  quartzite.  The  whole  group  is  exceedingly  ferruginous. 
Thin  seams  of  clay  ironstone  are  often  seen  to  separate  the  strata  of  sand- 
stone, and  many  of  the  shales  contain  large  quantities  of  iron.  Many  of  the 
sandstones  are  seen  to  be  ferruginous  on  the  interior  when  broken,  but  some 
of  the  beds  are  buff  and  light  gray  on  fresh  surfaces.  The  general  color 
of  the  walls  of  the  canons  and  mountain  escarpments  is  red  and  brown,  due 
to  the  more  complete  oxidation  of  the  iron.  In  the  canons  and  gulches, 
where  bays  of  quiet  water  are  formed,  considerable  accumulations  of  steel- 
gray  iron  sands  may  often  be  seen.  These  sometime  form  a  pigment  which 
the  Indians  of  the  region  were  accustomed  to  use  as  paint  in  former  days. 

The  great  mass  of  the  sandstones  are  fine  grained,  but  occasionally 
throughout  the  series  .strata  of  pebbles  are  found;  near  its  junction  with 
the  Red  Creek  Quartzite  these  are  conglomerates.  Those  peculiarities  or 
markings  of  strata,  known  as  ripple  marks,  are  very  abundant  at  many  hori- 
zons from  the  top  to  the  lowest  known  strata  and  mud  rills,  and  rain  drop 
impressions  are  sometimes  found.  A  very  few  concretions  have  been  found 
in  the  group.  Weeks  and  months  have  been  spent  in  the  search  yet  no  fos- 
sils have  been  found.  Within  the  territory  embraced  in  the  description  the 
base  of  the  group  is  never  seen.  The  Green  River  runs  along  the  axis  of 
the  Uinta  flexure  for  many  miles  but  its  bed  is  yet  in  the  Uinta  Sandstone 
so  that  it  is  impossible  to  determine  the  entire  thickness  of  the  group,  but 
that  which  is  exposed  has  a  wonderful  developement,  no  less  than  12,500 
feet  of  these  sandstones  and  shales  being1  seen. 

I  have  already  stated  my  reasons  for  considering  this  formation  to  be 
older  than  Carboniferous,  and  I  have  given  it  provisionally  a  Devonian  color 
on  the  map.  Professor  Marsh  in  his  article  in  the  American  Journal  of 
Science  and  Arts,  in  the  March  number  of  1871,  "On  the  geology  of  the 
eastern  Uinta  Mountains,"  in  speaking  of  these  formations  says,  "  *  *  *  * 
and  a  subsequent  examination  of  apparently  a  portion  of  the  same  series, 


142  GEOGRAPHIC  DISTRIBUTION. 

on  the  western  side  of  the  river,  rendered  it  probable  that  a  part  of  them  at 
least  are  of  Silurian  age."  In  that  article  the  professor  does  not  mention 
the  finding  of  any  fossils  in  the  formation,  and  on  what  facts  his  statement 
is  based  I  do  not  know ;  but  his  conclusion  is  entitled  to  great  consideration, 
for,  although  his  study  of  this  region  Was  of  short  duration,  he  fully  appre- 
ciated the  great  series  of  formations  brought  into  view  by  the  Uinta  upheaval, 
and  in  clear  comprehensive  language  gives,  in  the  article  mentioned,  a  sum- 
mary statement  of  the  structural  geology  of  the  eastern  Uintas. 

The  following  section  was  made  by  Mr.  John  F.  Steward  in  the  sum- 
mer of  1871.  It  commences  at  Beehive  Point  at  the  head  of  Red  Canon 
and  ends  at  the  foot  of  the  canon  where  the  river  debouches  into  Brown's 
Park.  Lower  members  of  the  group  are  seen  farther  down  the  river  but  are 
not  brought  into  the  section. 


UNTTA  SANDSTONE. 


143 


FIG.    12.— SECTION.   OF     UINTA     SANDSTONE     EXPOSED    IN 

RED    CANON. 


I. 

0 
2,000 

<J,  000 

\ 

0,000 

Xo.  1,  -J20  feet.     Arena- 
ceous shales  and  mi  nil  - 
stones;  gray,  pink,aml 
brown. 
Xo.  2,  285  feet,    Sand- 
stones anilarouaceons 
shales. 
c,  2  feet.    Sandstones  ; 
ilark  brown. 
b,  4  feet.    Shales;    not 
well  exposed. 
c,  3  feet.     Sandstones  ; 
gray  ;  coarse;  break  - 
i  i!  g    into    irregular  \ 
fragteents  on  expos- 
ure to  the.  weather. 
/I,  (in  feet.    Sandstones; 
dark   red;    not  well 
exposed. 
e,  7  feet.    Sandstones  ; 
pinkish-gray;  thinly 
and  irregularly  lam- 
innted. 
/,  lit  feet.    Arenaceous 
shales  ;  dark  purple; 
very  friable. 
g,  G  feet.    Sandstones  ; 
gray, 
/<,  xi  Let.     Arenaceous 
shales  ;    dark  gray 
and  purple  ;  not  well 
exposed. 
/,  ll'lifeet.  Sandstones; 
shaly. 
Dip  of  'tlie  above,  80°. 

Xo.  3,  334  feet.    Sand- 
stone: thickly  bedded; 
'•times    'coarse 
Drained  and  becoming 
a  line  conglomerate. 
No.  4,  3,108  feet    Dark 
sandstones  and  arena- 



_ 

1    C,  237 
8,000 

10,  000 
13,  000 

9,  95  feet.    Shales  ;  up- 
per  2J  feet   purple  : 
next  5  feet  greenish  ; 
all  below  brown. 
Average  dip,  20°. 

No.  5,  5,800  feet,     lied 
sandstones,  with  an 
occasional   thin    and 
inconstantstratum  of 
arenaceous    shale; 
sandstones  aud  con- 
glomerates in  many 
places  ;    the  lower 
members    containing 
:      manypebblesotwbitc 
quartzito.  These  beds 
are  so  massive    and 
homogeneous  as  not 
to  bo    easily    subdi- 
vided. 

-  '  •  -.-.1 

s 

/ 
_/!/.  °.r,c£^ 

z 
1 

i-  :'.^'.'_'~  '.'.'.'-'.•  '.^} 

--.•':'::--;''J::^ 

*&£-jM 

j  ••  ?  "af°°  <•    °   c.     «) 

-^  ..:::.-.  vj 

"-.'.*'*  X/.^;*:] 

v<^.~--  -  ,  *^  •  -  -'-.5*-y 

.-     .-      _.....k 

—  :  —  ;     ;    rT-    •  •  •  '\ 

:•..•-•-.:.../..  -,..-..-j 

—  .   -  -    -   -  —  —  —  -~~^~o 

rn^rn 

tW^t! 

ceous  shales  in  alter- 
nation. 
a,  150  feet.  Arenaceous 
shales  ;  dark  brown. 
ft.  ">(>  i'eet.  Sandstones  ; 
compact;  dark  red. 
c,  If)  feet.    Arenaceous 
shales;    thinly    and 
evenly  bedded. 
d,  11  5  feet.  Sandstones; 
massive  ;  dark  red. 
e,  30  feet.    Arenaceous' 
shales  and  thinly 
bedded  sandstones  ; 
reddish  brown. 
/,  r>  feet.    Sandstones; 
purple. 
!7,  "i  i'eet.     Arenaceous 
sliales  ;  ]>urplc. 
h,  20  feet.  Sandstones  ; 
massive  ;    coarse; 
purple, 
i,  50  feet.     Arenaceous 
shales  ;  purple  ;  not 
well  exposed. 
j,  270  feet.  Sandstones  ; 
red  ;  coarse. 
k,  5  feet.     Arenaceous 
shales;  g''ociiish  . 
rather  compact. 
1,  375  feet.  Sandstones  ; 
massive  ;  red. 
in,  18  feet.  Arenaceous 
shales  ;  dark  purple; 
tine  texture, 
n,  170  feet.  Sandstone; 
massive  ;  rod. 
o,  7f>0  feet.  Arenaceous 
shales  ;    purple  and 
red  above  ;  greenish 
in  middle,  aud  brown 
and  black  at  base. 

\tiMSm 

:•.  .:•.:•.:•.{ 

'^--  :vj.'-;::l 

•....-.•.•.ifr/J 

4 

-::•.-.  ::•-•.  --^ 

%&  2  <?"/,?  °2sf2»] 

/ 

mrn^ 

^  ^-I-E^ 

e   a    a0,"0  «     "    o'o°\ 

«"   °     "      00o"onr   C     C"°] 

=i=j? 

«»°0  0  ^  "    °«f>0  »  e    J) 

=f 

,,,^ 

massive;  purple  and 
brown. 

144  GEOGRAPHIC  DISTRIBUTION. 

A  good  section  can  be  obtained  by  passing-  over  the  6-wi-yu-kuts 
plateau.  On  the  northeast,  this  plateau  culminates  in  a  high  ridge  of  cherty 
and  brecciated  limestone  which  is  the  base  of  the  Red  Wall  Group.  By 
starting  at  the  eastern  extremity  and  foot  of  this  ridge  and  going  southwest- 
ward  across  the  plateau  and  descending  into  Brown's  Park  until  the  axis  ol 
the  flexure  is  reached,  you  pass  over  the  upturned  edges  of  the  Uinta  Sand- 
stone. This  section  gives  a  thickness  to  the  beds  of  more  than  13,000  feet. 
The  factors  used  in  the  measurement  were  the  distance  between  the  extrem- 
ities of  the  line  along  which  the  section  was  made  as  determined  by  the 
topographers,  and  the  observed  dips  along  the  line  at  subequal  distances 
of  about  200  yards.  In  1871  we  attempted  to  make  a  section  from  the  axis, 
through  the  Canon  of  Lodore,  but  the  difficulty  of  navigating  the  river  was 
so  great  that  we  could  not  perform  the  task  with  satisfaction;  but  the  thick- 
ness of  the  beds  found  along  this  line  was  not  less  than  13,000  feet. 

The  Uinta  Sandstone  crops  out  along  the  base  of  the  wall  through  the 
upper  part  of  Whirlpool  Canon.  On  the  north  side  of  the  Yanupa  Plateau, 
south  of  the  Yampa  River  there  is  a  monoclinal  flexure  and  fault  by  which 
the  Carboniferous  rocks  are  uplifted  several  thousand  feet.  There  are  three 
cations  running  across  this  displacement  which  cut  through  the  Carbonif- 
erous rocks  and  reveal  in  their  walls  several  hundred  feet  of  the  upper 
members  of  the  Uinta  Group.  The  anticlinal  uplift  which  forms  Junction 
Mountain  is  bisected  by  the  Yampa  River.  The  gorge  through  which  the 
river  runs  is  called  Junction  Mountain  Canon.  In  the  heart  of  the  canon 
Uinta  Sandstones  are  seen. 

UNCONFORMITY  AT  THE  SUMMIT  OF  THE  UINTA  GROUP. 

A  period  of  erosion  or  dry  land  condition  intervened  between  the  deposi- 
tion of  the  Uinta  Sandstones  and  of  the  Carboniferous  Groups, 

In  Whirlpool  Cm! on  the  red  sandstones  of  the  Uinta  Group  are  thrust 
up  into  the  sandstones  and  shales  of  the  Lodore  Group,  and  in  some  cases 
almost  sever  them;  that  is.  the  Uinta  Sandstones  were  deeply  eroded  into 
abrupt  valleys  with  steep  cliffs,  some  of  them  400  feet  high,  anterior  to  the 
deposition  of  the  Lodore  Group.  There  is  a  difference  of  dip  between  the 


UNCONFORMITY   OF  THE  SUMMIT  OF  THE  UINTA  GKOUP.       145 

two  groups  of  about  four  degrees,  the  lower  group  having  the  greater  incli- 
nation to  the  south. 

The  following  section  illustrates  the  facts  observed  here : 


1,000  5,000  feet. 

R.  Red  "Wall  Group.    L.  Lodore  Group.    V.  Uinta  Group. 

Fig.  13. — Section  showing  the  unconformity  between  the  Lodore  and  Uinta  Groups  in  Whirlpool 
Canon. 

At  the  foot  of  the  Caiioii  of  Lodore  the  unconformity  is  represented  by 
a  difference  of  dip  of  from  5  to  6  degrees,  and  the  Lodore  Group  steadily 
overlaps  the  upper  members  of  the  Uinta  Group,  cutting  off  more  than 
2,000  feet  of  the  latter.  Here,  also,  the  Uinta  Sandstone  is  protruded  into 
the  Lodore  shales.  These  facts  are  illustrated  in  the  following  section : 


5.000  feet. 

R.  Red  Wall  Group.    L.  Lodore  Group.     U.  Uinta  Group. 
Fig.  14. — Section  showing  the  unconformity  between  the  Lodore  and  Uinta  Groups  in  the  Canon 

of  Lodore. 

On  the  northeast  side  of  the  0-wi-yu-kuts  Plateau  the  Lodore  Group 
is"  wanting,  and  the  massive  limestone  at  the  base  of  the  Red  Wall  Group 
rests  upon  the  Uinta  Sandstone.  In  passing  from  the  northwest  end  of  the 
ridge  along  the  strike  of  the  sandstone  to  the  southeast,  the  upper  beds 
of  the  Uinta  Sandstone  are  seen  to  disappear,  having  been  cut  off  by  erosion 
before  the  deposition  of  the  limestone,  and  there  is  from  one  to  two  thou- 
sand feet  more  of  the  Uinta  Sandstone  at  the  former  end  of  the  ridge  than 
at  the  latter.  • 

This  unconformity  can  also  be  seen  in  the  cation  of  Junction  Mountain, 
and  it  has  been  observed  on  the  southern  side  of  the  Uinta  Mountains,  west 
of  the  district  covered  by  the  map,  in  the  canon  cut  by  the  tributaries  of  the 

Uinta  River.   • 
10  p  ci 


146  GEOGRAPHIC  DISTRIBUTION. 

THE  CARBONIFEROUS  GROUPS. 
CERTAIN  GEOGRAPHIC    DISTRICTS    DESIGNATED. 

In  describing  the  geographic  distribution  of  the  Carboniferous  and 
Mesozoic  Groups  it  will  be  found  convenient  to  designate  under  general 
terms  certain  districts  of  country,  as  follows : 

FLAMING    GORGE    DISTRICT.      . 

There  is  a  belt  of  country,  extending  from  Bruce  Mountain  westward 
to  the  border  of  the  map,  where  most  of  the  Carboniferous  and  Mesozoic 
arid  certain  of  the  Cenozoic  formations  are  turned  up  on  edge,  so  that  in  a 
limited  area  nearly  all  these  groups  can  be  studied.  The  Green  Eiver  enters 
the  Uinta  Mountains  by  a  flaring,  brilliant,  vermilion  gorge,  a  conspicuous 
and  well  known  locality,  to  which,  several  years  ago,  I  gave  the  name 
Flaming  Gorge,  and  this  name  has  been  generally  accepted.  I  shall  call 
this  the  Flaming  Gorge  district. 

PO    CANON    DISTRICT. 

East  of  Bruce  Mountain,  for  many  miles,  the  Uinta  displacement  is 
chiefly  by  faulting,  and  with  slight  exception  the  Carboniferous  and  Meso- 
zoic Groups  have  been  carried  down  and  are  concealed.  But  southeast 
from  Diamond  Peak  the  displacement  changes  again  into  a  flexure,  and  once 
more  the  Carboniferous  and  Meaozoic  Groups  are  found  turned  up  on  edge. 
This  region  is  at  the  eastern  end  of  the  0-wi-yu-kuts  Plateau,  the  plateau 
itself  culminating  in  a  high  monoclinal  ridge  at  its  eastern  extremity,  and 
the  plateau  is  bounded  on  this  side  by  a  deep  monoclinal  canon  which  divides 
it  from  a  region  of  Mesozoic  and  higher  Carboniferous  hogbacks.  This 
canon  is  also  a  well  marked  and  well  known  geographic  feature.  Some 
years  ago  I  gave  it  the  name  Po  Canon,  and  that  name  has  been  accepted 
throughout  the  country.  This  I  shall  call  the  Po  Canon  district.  • 

YAMPA    DISTRICT. 

In  the  Yampa  Plateau  by  a  series  of  flexures  and  faults  the  whole  Meso- 
zoic and  Carboniferous  series  are  brought  to  view.  East  from  the  Yampa 
Plateiiu  there  is  a  simple  anticlinal  upheaval  where  all  these  groups  are 


CERTAIN  GEOGEAPIC  DISTRICTS  DESIGNATED.  147 

again  seen.  I  shall  call  the  Yampa  Plateau  and  adjacent  country,  together 
with  the  region  embraced  in  the  Junction  Mountain  uplift,  the  Yampa  dis- 
trict. 

ISLAND    PARK    DISTRICT. 

Finally,  west  of  the  lower  end  of  the  Canon  of  Lodore  and  Whirlpool 
Canon  there  is  a  zone  stretching  to  the  westward  where  all  these  groups 
are  in  like  manner  exposed.  At  the  foot  of  Whirlpool  Canon  lies  the  beau- 
tiful valley  known  as  Island  Park,  which  is  embraced  in  this  zone.  I  shall 
call  this  the  Island  Park  district. 

LODORE  GROUP. 

This  group  of  rocks  is  seen  in  Lodore  Canon,  from  which  locality  it 
takes  its  name.  Here  it  fills  valleys  in  the  Uinta  Sandstone  and  buries  the 
ancient  cliffs  and  hills  of  the  dry  land  period.  These  facts  were  set  forth  in 
the  last  section. 

The  group  is  composed  of  soft  sandstones  and  shales  with  conglomerates 
at  the  base  and  against  the  ancient  hill  sides.  Its  outcrop  on  the  northwest 
side  of  the  cation  is  of  very  limited  extent  and  is  not  represented  on  the  map, 
but  on  the  southeast  side  of  the  canon  it  mounts  the  wall  for  several  miles 
and  appears  in  Dunn's  Cliff,  where  its  thickness  was  measured  and  found  to 
be  460  feet.  Its  outcrop  is  represented  on  the  map  by  a  narrow  line.  On 
the  north  side  of  the  Uinta  Mountains  these  rocks  have  been  seen  at  but  one 
point,  viz,  a  little  west  of  Beehive  Point,  and  there  is  some  uncertainty  about 
this  observation.  Carboniferous  fossils  have  been  found  in  these  beds. 

The  area  of  the  outcrop  at  the  bottom  of  Whirlpool  Canon  is  so  narrow 
that  the  color  has  not  been  introduced  on  the  map  in  that  locality. 

RED    WALL    GROUP. 

Extensive  outcrops  of  the  Red  Wall  Group  are  found  on  the  flanks  of 
the  Uinta  Mountains.  On  the  north  side  the  entire  group  is  composed 
chiefly  of  limestone,  many  of  the  beds  being  cherty.  On  the  south  side  of 
the  mountains  many  sandstones  are  intercalated  with  the  limestone.  About 
ten  miles  from  Flaming  Gorge  in  a  southwestely  direction,  these  beds  are 
found  dipping  to  the  north,  and  as  they  are  followed  along  the  strike  to  the 


148  GEOGKAPHIC  DISTRIBUTION. 

westward  they  are  seen  to  rise  in  a  high  monoclinal  ridge.  This  ridge  is 
not  well  developed  until  we  pass  beyond  the  area  embraced  on  the  map. 
Another  outcrop  is  seen  on  the  northwest  corner  of  the  6-wi-yu-kuts  Pla- 
teau ;  here  the  beds  are  standing  vertically.  On  the  eastern  end  of  the  same 
plateau,  in  the  Po  Canon  district,  another  outcrop  appears  where  the  beds  dip 
a  little  north  of  east  in  a  lofty  monoclinal  ridge.  The  central  mass  of  Junction 
Mountain  is  Red  Wall  limestone,  and  the  group  crops  out  in  an  unbroken 
but  irregular  zone  along  the  south  side  of  the  Uinta  Mountains  on  the  east 
side  of  the  Canon  of  Lodore,  in  the  Escalante  Peaks,  and  on  the  west  side  of 
the  Canon  of  Lodore  in  the  Island  Park  district.  The  Ti-ra-yu-kuts  like 
the  Escalante  Peaks  are  composed  of  the  hard  cherty  limestones  of  the  Red 
Wall  Group  and  are  true  flanking  peaks.  Here  the  beds  all  dip  to  the  south 
usually  at  a  rather  low  angle,  and  along  the  northern  margin  of  the  outcrop 
the  cherty  limestones  stand  in  peaks.  Another  outcrop  is  seen  at  the  bot- 
tom of  Split  Mountain  Canon,  and,  last,  these  limestones  are  exposed  on  the 
Yampa  Plateau  on  an  escarpment  formed  by  a  fault  or  a  monoclinal  flexure 
which  faces  the  Yampa  River,  and  which  is  crowned "  by  many  towering 
peaks. 

All  these  outcrops  are  well  represented  on  the  map. 


LOWER   AUBREY    GROUP. 


This  group  is  made  up  of  rather  soft  sandstones  with  intercalated  lime- 
stones; altogether  the  rocks  are  much  more  friable  than  the  last  mentioned 
group,  and  they  also  yield  much  more  readily  to  atmospheric  degradation 
than  the  beds  of  the  Upper  Aubrey.  Where  the  beds  of  the  Red  Wall  and 
Upper  Aubrey  Groups  stand  in  monoclinal  ridges  the  beds  of  the  Lower 
Aubrey  are  found  in  the  inter-ridge  or  valley  spaces.  It  is  seen  outcropping 
in  the  vicinity  of  Flaming  Gorge  and  extending  in  a  narrow  zone  westward 
beyond  the  region  embraced  on  the  map.  On  the  east  side  of  the  0-wi-yu- 
kuts  Plateau  its  outcrop  can  be  traced  along  the  eastern  base  of  the  mono- 
clinal ridge,  which  is  composed  of  Red  Wall  limestones  as  described  above. 
Here  the  valley  lies  between  the  two  monoclinal  ridges  and  is  known  as  Po 
Canon.  These  beds  are  also  found  on  both  flanks  of  the  Yampa  Plateau 
and  along  the  southern  slope  of  the  Uinta  Mountains  from  its  eastern  extrein- 


LOWEE  AUBREY— UPPEE  AUBEEY.  149 

ity  in  a  narrow  zone  to  the  western  border  of  the  region  under  discussion. 
These  beds  outcrop  again  in  Split  Mountain  Canon  in  a  deep  gulch  running 
westward  from  its  head,  and  again  on  the  Yampa  Plateau.  Here  some  of 
its  harder  limestones  are  occasionally  found  standing  in  low  peaks. 

UPPER  AUBREY  GROUP. 

In  the  Uinta  Mountains  the  Upper  Aubrey  is  composed  of  two  mem- 
bers, a  massive,  homogeneous,  light  gray  sandstone  at  the  base,  which  I 
have  called  the  Yampa  Sandstone,  having  a  thickness  of  a  thousand  feet  or 
more;  and  above,  a  cherty  limestone  from  150  to  200  feet  in  thickness,  which 
I  have  -called  the  Bellerophon  Limestone.  These  beds  from,  their  indura- 
tion and  homogeneity  are  well  adapted  to  the  formation  of  ridges. 

The  group  is  seen  outcropping  in  the  Flaming  Gorge  district,  and  in 
a  zone  stretching  westward  from  Horseshoe  Canon  for  many  miles.  A  little 
patch  has  been  caught  in  the  fault  on  the  west  side  of  Quartz  Mountain  and 
thrust  between  strata  of  Cretaceous  Age,  and  its  area  is  marked  on  the  map. 
The  monoclinal  ridge  on  the  east  side  of  Po  Canon  is  of  this  age.  It  is  seen 
on  all  sides  of  Junction  Mountain.  Yampa  Canon  is  carved  through  this 
sandstone.  Here  the  rocks  dip  to  the  south  and  the  homogeneous  Yampa 
Sandstone  on  the  north  side  of  the  canon  is  cut  by  a  multitude  of  little  can- 
ons, the  channels  of  rainy  day  brooks.  The  entire  slope  is  minutely  carved 
in  this  manner  and  the  spaces  between  the  meandering  canons  in  many 
places  are  but  narrow  walls,  and  sometimes  these  walls  are  broken  where 
the  channels  approach  too  closely,  and  by  this  process  buttes  with  narrow 
bases,  and  towers  and  pinnacles  are  formed.  Along  the  courses  of  these 
intermittent  streams  great  numbers  of  pot-holes  are  found.  This  topography 
is  too  minute  to  be  represented  on  the  map.  On  the  eastern  end  of  the 
Yampa  Plateau  this  sandstone  forms  the  slope  of  the  plateau  where  it  de- 
scends into  the  valley,  and  is  in  like  manner  carved  with  innumerable 
gulches  whose  courses  are  interrupted  by  pot-holes. 

This  group  has  an  extensive  outcrop  in  the  Yampa  Plateau,  and  finally 
it  has  been  traced  from  Whirlpool  Canon  westward  beyond  the  limits  of  the 
map. 


(50  GEOGRAPHIC  DISTRIBUTION. 

The  outcrop  of  these  Carboniferous  groups  has  been  traced  from  point  to 
point  throughout  the  areas  described  above.  In  most  places  the  exposures  are 
complete  and  the  relations  of  the  -beds  can  be  well  understood,  and  nowhere 
has  any  unconformity  between  its  members  been  observed.  Nor  has  any 
unconformity  between  the  Upper  Aubrey  and  the  lower  Mesozoic  been 
observed;  but  as  the  lowest  beds  of  Mesozoic  Age  are  of  very  friable  ma- 
terial, the  exact  junction  is  rarely  seen. 

In  the  line  of  the  fault  between  the  Flaming  Gorge  district  and  the  Po 
Canon  district  there  is  a  fragment  of  Red  Wall  limestone,  as  seen  on  the 
map,  on  the  northwest  corner  of  the  (3-wi-yu-kuts  Plateau,  which  was  not 
carried  down  by  the  fault ;  i.  e.,  the  fault  is  to  the  north. 

JTJKA  TRIAS  GROUPS. 

SHINARUMP    GROUP. 

These  beds  are  shales  and  soft  sandstones,  and  hence  in  this  region, 
which  is  plicated,  they  are  found  in  valley  spaces.  The  Lower  Aubrey  on 
one  side  and  the  Vermilion  Cliff  on  the  other  stand  in  ridges.  At  the  foot 
of  the  cliff  on  the  south  side  of  Flaming  Gorge  the  Green  River  runs  into 
the  beds  of  this  age  and  soon  passes  across  them  to  enter  the  Upper  Aubrey 
beds.  Looking  westward  a  towering  cliff  is  seen  on  the  right  and  a  .broken 
slope  on  the  left  and  a  narrow  valley  immediately  in  front,  which  may  be 
followed  untir  the  bank  of  Sheep  Creek  is  reached ;  then  turning  up  Sheep 
Creek  that  stream  is  found  to  run  nearly  its  entire  course,  as  represented 
on  the  map,  in  beds  of  this  age.  The  steep  wall  of  vermilion  sandstone  on 
the  north  side  of  this  valley  is,  except  at  one  point,  an  impassable  barrier. 
Eastward  from  Flaming  Gorge  the  outcrop  of  the  Shinarump  Group  is  seen 
in  a  narrow  valley  between  two  ridges,  for  about  six  miles,  until  it  is  cut  off 
by  the  great  Uinta  fault. 

Outcrops  are  also  found  in  the  Po  Canon  district.  Here  again  the  beds 
are  found  in  the  spaces  between  the  ridges.  The  same  is  true  along  the 
foot  of  the  Yampa  Plateau  to  the-  east,  south,  and  west ;  and  also  in  a  general 
way  in  its  outcrop  from  the  foot  of  Whirlpool  Canon  through  the  Island 
Park  district.  But  this  topographic  peculiarity  is  not  shown  on  the  map  in 


JURA  TRIAS  GROUPS. 


the  last  mentioned  region,  as  the  area  of  the  outcrop  of  all  of  the  Jura  Trias 
beds  has  its  topography  cut  up  so  minutely  by  reason  of  many  minor  dis- 
placements and  transverse  lines  of  erosion  that  only  a  generalized  represen- 
tation could  be  given. 

There  is  an  island  of  Shinarump  beds  south  of  Echo  Park,  lying  at  the 
foot  of  the  Yampa  Plateau. 

VERMILION   CLIFF,    WHITE    CLIFF,    AND   FLAMING   GORGE    GROUPS 

In  this  region  the  Vermilion  Cliff  and  White  Cliff  Groups  are  massive 
sandstones,  and  hence  stand  in  monoclinal  ridges.  Sometimes  the  base  of 
the  White  Cliff  Group  is  a  series  of  softer  beds,  and  two  ridges  are  formed. 
Elsewhere  the  White  Cliff  Group  rises  high  over  the  Vermilion  Cliff  beds  in 
a  wall  which  faces  the  axis  of  the  Uiiita  upheaval  on  either  side.  Through- 
out this  entire  region  the  White  Cliff  sandstone  is  lighter  colored  than  the 
Vermilion  Cliff  Group  and  everywhere  exhibits  that  oblique  structure  known 
as  false  bedding. 

The  Flaming  Gorge  Group  with  its  limestones  and  sandstones  is  of 
heterogeneous  stratification  and  breaks  down  into  comparatively  low  hills, , 
which  are  found  on  the  backs  of  the  great  White  Cliff  ridges.  The  area  of 
outcrop  is  parallel  and  coextensive  with  that  of  the  Shinarump  Group,  except 
in  the  region  near  Flaming  Gorge  and  the  district  immediately  south  of  Echo 
Park. 

About  four  miles  southeast  from  Diamond  Peak  there  is  a  small  outcrop 
of  the  Flaming  Gorge  beds  standing  on  edge,  with  the  summit  of  the  group 
'facing  the  plateau  or  axis  of  the  Uinta  upheaval. 

It  is  an  interesting  fact  that  the  bad-land  sandstones  of  the  Flaming 
Gorge  Group,  both  above  and  below  the  Mid-Group  Limestone,  are  of  fresh- 
water origin. 

The  following  is  a  section  of  the  Jura  Trias  groups,  made  in  the  hills 
and  cliffs  west  of  Flaming  Gorge  and  beginning  above  at  the  base  of  the 
conglomerate  which  underlies  the  teleost  shales,  and  extending-  to  the  summit 

O  /  d 

of  the  Bellerophon  Limestone.  In  this  region  the  limits  of  the  section  can 
be  easily  determined. 


152  GEOGRAPHIC  DISTRIBUTION. 

SECTION  OF  THE  JURA  TRIAS  GROUPS. 
FLAMING    GOEGE    GROUP. 

No.  1,  110  feet. — Gray,  greenish  gray,  pink,  purple,  and  chocolate 
beds ;  very  friable ;  bad -land  beds. 

No.  2, '200  feet.- — Bluish-gray  limestone;  Mid-Group  Limestone. 

No.  3,  500  feet. — Coarse  red  sandstone ;  (unio  beds.) 

No.  4,  250  feet. — Limestone;  bluish-buff;  compact;  sometimes  slialy 
and  interstratified  with  orange  shales  and  thin  beds  of  gypsum. 

WHITE    CLIFF    GROUP. 

No.  5,  1,025  feet. — Massive  sandstone ;  light  gray  and  light  orange, 
everywhere  exhibiting  false  stratification  in  many  directions  and  at  many 
angles. 

VERMILION    CLIFF    GROUP. 

No.  6,  300  feet. — Sandstone ;  massively  bedded ;  gray,  drab,  and  brown 
within,  but  weathering  with  bright  vermilion  surfaces ;  well  exposed  on  the 
summit  of  Flaming  Gorge. 

No.  7,  6  feet. — Shales,  somewhat  argillaceous. 

No.  8,  359  feet. — Sandstones ;  rather  friable,  with  intercalated  shales ; 
the  latter  containing  much  gypsum ;  weathering  in  variegated  blight  colors. 

SHIN^.RUMP    GROUP. 

No.  9,  1,095  feet. — Shales  and  sandstones  containing  much  gypsum; 
weathering  in  many  colors,  but  brown  and  chocolate  tints  prevailing;  in 
many  places  constituting  bad-land  beds. 

These  beds  all  dip  to  the  north  at  a  great  angle. 

*•******•**#•*  -x- 

It  will  be  seen  that  the  Jura  Trias  groups  are  exposed  in  outcrops  on 
the  north  side  of  the  Uinta  Mountains  in  isolated  patches,  and  these  out- 
cropping beds  in  the  Flaming  Gorge  district  dip  to  the  northward.  In  the  Po 
Canon  district  they  dip  in  a  direction  a  little  north  of  east.  These  two  areas 
of  outcrop  are  separated  by  a  long  space  where  these  groups  are  carried  down 
by  the  great  Uinta  fault,  and  their  non-appearance  at  the  surface  is  due 


THE  CRETACEOUS  GROUPS.  153 


i 


chiefly  to  this  cause,  as  they  are  not  usually  covered  on  this  side  of  the 
range  by  unconformable  Tertiaries.  The  exceptions  will  be  noted  hereafter. 

On  the  eastern  end  of  the  Uinta  Mountains,  between  the  Po  Canon 
district  and  the  Junction  Mountain  region,  the  upturned  edges  of  Jura  Trias 
rocks  occasionally  protrude  through  the  overlying  unconformable  beds  of 
Brown's  Park  age,  but  these' protruding  masses  are  too  small  to  be  shown 
on  the  map. 

About  the  Junction  Mountain  uplift  the  eroded  edges  of  the  Trias  are 
sometimes  buried  beneath  unconformable  beds  of  Brown's  Park  acre. 

o 

On  the  south  side  of  the  Uinta  Mountains  the  area  of  outcrop  of  the 
Jura  Trias  groups  is  very  much  greater.  Near  the  head  of  Ashley's  Creek 
the  three  upper  groups  of  the  Jura  Trias  are  buried  by  unconformable  rocks 
of  Tertiary  Age.  Farther  west,  beyond  the  area  covered  by  the  map,  these 
unconformable  Tertiary  rocks  ride  high  up  on  the  groups  of  Carboniferous 

beds. 

THE  CRETACEOUS  GROUPS. 

The  Henry's  Fork  Group,  which  is  the  lowest  Cretaceous  formation, 
has  an  outcrop  parallel  and  approximately  co-extensive  with  the  several 
groups  of  Jura  Trias;  that  is,  like  those  groups  it  was  brought  up  by  the 
great  Uinta  upheaval  and  the  elevation  of  the  Yampa  Plateau.  The  same 
is  true  of  the  higher  Cretaceous  groups,  but  the  latter  ate  also  brought  into 
view  in  the  Aspen  Mountain  upheaval ;  and  hence,  in  the  discussion  of  the 
geographic  distribution  of  these  formations  it  is  necessary  to  refer  to  a  dis- 
trict of  country  not  heretofore  mentioned  in  connection  with  the  Carbon- 
iferous or  Jura  Trias  groups. 

I  shall  call  this  the  Aspen  Mountain  district. 

HENRY'S  FORK  GROUP. 

Nothing  further  need  be  said  of  the  geographic  occurrence  of  this  form- 
ation. The  group  is  composed  of  sandstones,  indurated  arenaceous  shales, 
and  conglomerates.  These  shales  ring  under  the  hammer,  and  are  of  steel- 
gray  color,  and  rarely  afford  footing  to  vegetation,  and  can  be  traced  in  a 
bright  band  everywhere  through  the  outcrop  of  the  formation.  The  con- 
glomerates contain  many  gravels  and  bowlders  of  pre-existing  schistic  rocks. 


154  GEOGRAPHIC  DISTRIBUTION. 

They  have  a  much  more  extensive  development  on  the  south  than  on  the 
north  side  of  the  Uinta  Mountains. 

.  On  the  south  side  of  the  Yampa  Plateau,  where  the  Fox  Creek  and 
Cliff  Creek  flexures  unite,  the.se  conglomerates  stand  on  edge  with  a  dip  of 
about  85  degrees  to  the  southeast,  and  are  firmly  cemented,  and  stand  as 
high  walls,  separated  by  a  long,  narrow  valley,  strewn  with  fragments  of 
the  conglomerate  which  have  tumbled  down  from  either  side.  Farther  east, 
along  the  southern  slope  of  the  Yampa  Plateau,  they  are  very  conspicuous 
features  in  the  topography,  as  they  are  found  standing  in  ridges  and  monu- 
ments. Here  the  topography  is  exceedingly  complex,  too  much  so  to  be  rep- 
resented on  the  map  which  presents  but  a  crude  generalization  of  the  many 
wonderful  features  of  this  region. 

SULPHUR    CEEEK    GEOUP. 

These  beds  are  soft  argillaceous  and  arenaceous  shales  of  dark  color, 
but  sometimes  weathering  a  light  gray.  By  reason  of  their  exceeding  fria- 
bility the  areas  of  outcrop  are  everywhere  valley  regions,  often  diversified 
with  broad  stretches  of  low,  bad-land  hills  in  many  places  quite  naked  of 
vegetation,  but  elsewhere  covered  with  patches  of  cactacece.  Conspicuous 
among  these  is  a  species  of  opuntia,  with  its  minute,  subtle  thorns  hedging 
the  hills  with  a  threat  of  festering  wounds. 

Its  most  extensive  area  of  outcrop  is  in  the  Island  Park  sag,  and  it  has 
a  small  outcrop  in  the  northern  portion  of  the  Aspen  Mountain  uplift. 

A  fragment  of  these  beds  is  seen  southeast  of  Diamond  Peak,  which, 
with  a  fragment  of  the  Flaming  Grorge  beds  on  one  side  and  a  fragment  of 
Salt  Wells  on  the  other,  is  standing  on  edge.  It  will  be  noticed  that  these 
beds  dip  toward  the  axis  of  upheaval,  that  is,  the  highest  beds  are  found 
nearest  the  mountain,  and  they  all  stand  with  an  inclination  from  the  horizon 


of  90  degrees. 


SALT    WELLS    GEOUP. 


It  is  unnecessary  to  speak  in  detail  of  the  outcrop  of  the  Salt  Wells 
beds,  as  the  attention  of  the  reader  has  already  been  called  to  the  outcrop 
on  the  flanks  of  the  Uinta  Mountains  and  in  the  Aspen  Mountain  district. 
It  is  worthy  o.f  remark  that  in  the  Uinta  Mountain  region  these  beds  are 


THE  CRETACEOUS  GROUPS.  155 

usually  friable  arenaceous  and  argillaceous  shales,  while  in  the  Aspen 
Mountain  district  they  are  arenaceous  shales  and  thinly  bedded  sandstones, 
itiid  the  greater  induration  of  some  of  the  beds  in  the  last  mentioned  dis- 
trict causes  the  valley  spaces,  which  are  characteristic  of  this  group,  to  be 
diversified  with  low  ridges  and  cliffs. 

POINT    OF    ROCKS    GROUP. 

The  beds  of  this  group  can  usually  be  divided  into  three  somewhat 
well  defined  members,  the  Upper  Hogback,  Middle  Hogback,  and  Golden 
Wall  Sandstones,  which  are  usually  separated  by  a  few  feet  of  shaly  sand- 
stones, and  these  stratigraphic  characteristics  under  conditions  of  upheaval 
and  erosion  usually  result  in  the  production  of  three  ridges,  which  are  the 
topographic  features  giving  names  to  the  several  members.  The  upper 
sandstone  is  usually  massive  and  of  light  gray  color  weathering  unequally 
on  exposed  surfaces,  which  inequality  is  not  determined  by  lines  of  stratifi- 
cation. Here  an  irregular  mass  tumbles  down  and  a  cave  is  formed ; 
there  an  irregular  mass  is  more  indurated  than  the  general  body  to  which 
it  belongs  and  stands  in  relief,  often  in  some  fantastic  form;  and  such 
weathering  gives"  the  cliffs  which  are  usually  found  along  the  outcrop  of 
these  beds  a  strange  and  weird  appearance.  The  general  structure  is  sub- 
concretionary,  and  true  concretions  sometimes  weather  out.  The  same 
weathering  is  sometimes  found  in  the  Middle  Hogback  Sandstone. 

The  Golden  Wall  Sandstone  is  often  homogeneous  and  of  a  bright 
yellow  color  in  the  Uinta  region,  and  often  stands  as  a  sheer  wall ;  hence 
its  name ;  but  in  the  Aspen  Mountain  district  these  yellow  sandstones  are 
broken  into  strata,  and  light  gray  sandstones  and  shales  are  intercalated. 
The  ridge  like  topography  characteristic  of  this  group  of  beds  so  preva- 
lent everywhere,  renders  it  easy  to  trace  every  outcrop,  and  the  peculiar 
and  persistent  characteristics  of  the  upper  member  greatly  facilitate  the 
study  of  the  relation  between  the  Cretaceous  below  and  Tertiary  groups 
above.  In  the  Uinta  Mountains  the  unconformity  at  this  horizon  is  every- 
where apparent.  The  difference  in  dip  is  from  two  to  fifteen  degrees,  and 
the  evidence  of  intervening  erosion  is  apparent ;  but  in  the  Aspen  Mountain 


J56  GEOGEAPHIC  DISTEIBUTION. 

country  the  difference  of  dip  is  not  easily  distinguished,  but  the  evidences 
of  erosion  are  usually  apparent. 

No  evidence  of  unconformity  between  the  Cretaceous  formations  has 
been  discovered,  and  the  planes  of  demarkation  in  many  places  are  not  well 
exhibited.  In  such  a  case  the  lines  are  drawn  on  the  map  only  as  approxi- 
mations. Nor  is  there  any  evidence  of  unconformity  between  the  lowest 
Cretaceous  and  the  highest  Jura.  Here,  also,  the  stratigraphic  plane  is 
sometimes  obscure.  The  teleost  shales  contain  the  lowest  Cretaceous  fossils 
which  have  yet  been  found,  and  the  bad-land  beds  below  the  conglomerates 
contain  the  highest  Jurassic  fossils  found.  The  intervening  conglomerates 
I  have  thought  best  to  call  Cretaceous. 

In  a  general  way  the  horizon  of  conglomerates  can  be  easily  traced ; 
still,  it  is  a  variable  one.  Here  the  sandstones  are  found  with  conglom- 
erates of  small  pebbles  which  cannot  be  easily  separated  from  the  sand- 
stones as  they  merge  into  them  by  imperceptible  gradations.  Elsewhere 
well  developed  conglomerates  are  found,  and  sometimes  heavy  beds  of 
coarse  conglomerate  prevail. 

*  *  *  *  *  *  * 

The  following  section  of  the  Cretaceous  Groups  was  made  on  the  east 
side  of  the  Green  River  above  Flaming  Gorge. 

POINT    OF    ROCKS    GROUP. 

Upper  Hogback  Sandstone.— No.  1,  60  feet.  Sandstones;  indurated; 
light  gray ;  stained  in  patches  with  iron. 

No.  2,  60  feet.  Sandstones ;  gray ;  on  exposed  surfaces  stained  brown 
with  iron ;  containing  fragments  of  coal. 

No.  3,  25  feet.  Sandstones ;  very  massive ;  light  gray. 

No.  4,  5  feet.  Carbonaceous  shales,  with  seams  of  coal. 

No.  5,  35  feet.  Sandstones ;  indurated ;  gray. 

No.  6,18  feet,  Carbonaceous  shales,  with  seams  of  coal. 

No.  7,  80  feet.  Sandstones  ;  indurated ;   dark  gray. 

No.  8,  60  feet.  Sandstones ;  massive ;  light  gray. 

No.  9,  4  feet.  Carbonaceous  shales,  with  seams  of  coal. 


SECTION  OF  THE  CRETACEOUS  GROUPS.  157 

No.  10,  110  feet.  Sandstones;  homogeneous;  massive;  light  gray; 
indurated. 

Middle  Hogback  Sandstone. — No.  11,  275  feet  Sandstone ;  buff;  heavily 
bedded  with  intercalated  shales  and  seams  of  ferruginous  clay. 

No.  12,  75  feet.  Friable  sandstones  and  carbonaceous  shales. 

Golden  Wall  Sandstone. — No.  13,  600  feet.  Sandstones;  yellow;  rather 
massively  bedded,  with  intercalated  carbonaceous  shales. 

No.  14,  80  feet.  Sandstone ;  massive ;  bright  yellow. 

All  the  beds  of  the  above  group  dip  to  the  north  about  45  degrees. 

SALT    WELLS    GROUP. 

No.  15?  1,860  feet.  Friable  sandstones  and  arenaceous  shales. 

SULPHUR  CREEK  GROUP. 

No.  16,  2,000  feet.  Dark  argillaceous  and  arenaceous  shales. 

HENRY'S  FORK  GROUP. 

No.  17,  25  feet.  Conglomerates;  pebbles  very  small,  the  largest  not 
being  more  than  half  an  inch  in  diameter. 

No.  18,  80  feet.  Sandstones;  mottled  light  gray  and  yellow;  showing 
false  stratification. 

No.  19,  70  feet.  Shales;  (teleost  shales.) 

No.  20,  135  feet.  Sandstones ;  rather  heavily  bedded  above,  but  thinly 
bedded  below ;  drab. 

No.  21,  40  feet.  Sandstones;  coarse;   buff. 

No.  22,  100  feet.  Sandstones':  very  friable;  gray,  greenish-gray,  pink, 
purple,  and  chocolate. 

No.  23,  50  feet.  Sandstones ;  coarse ;  sometimes  appearing  as  a  con- 
glomerate of  fine  pebbles. 

No.  24,  100  feet.  Sandstones;  gray,  greenish-gray,  pink,  purple,  and 
chocolate ;  very  friable. 

No.  25,  75  feet.  Conglomerate ;  dark ;  in  some  places  a  coarse  sand- 
stone. 

******* 


153  GEOGEAPHIC  DISTRIBUTION. 

Below  I  reproduce  the  section  made  by  Professor  Meek  oh  Sulphur 
Creek  to  which  reference  has  been  made  in  a  previous  chapter.  I  copy  his 
numbers  and  characterization  of  the  beds,  but  group  them  in  accordance 
with  the  scheme  presented  in  this  report.  I  also  invert  the  order. 

SECTION  OF  THE  EOCKS  EXPOSED  ON  SULPHUE  CEEEK,  NEAE  BEAE 

EIVEE,  WYOMING. 

POINT    OF    ROCKS    GROUP. 

No.  1  (28),  200  feet. — Numerous  thin  seams  and  layers  of  dark  car- 
bonaceous shales,  with  harder  thin  bands  of  various  colored  argillaceous, 
arenaceous,  and  calcareous  matter,  including  a  few  very  thin  streaks  of  coal ; 
the  whole  being  highly  charged  with  vast  numbers  of  fresh  and  brackish- 
water  shells,  such  as  species  of  UniOj  Corbicula,  Gorbula,  Pyrgulifera,  Viri- 
parus,  Melampus,  & c.  Dip  nearly  east,  about  75°  below  the  horizon;  thick- 
ness 175  to  200  feet  exposed. 

No.  2  (27). — A  long  space  of  perhaps  260  yards  or  more,  with  only  a 
few  low  exposures  of  light-gray  sandstone,  showing  a  slight  westward  dip. 

No.  3  (26),  80  feet. — Gray  sandstone  in  place,  apparently  connected 
with  some  masses  (that  may  not  be  in  place)  so  as  to  include  space  enough 
for  60  to  80  feet, — forms  crest  of  a  hill. 

No.  4  (25),  800  feet. — Brownish  and  reddish  clays  with  a  few  distantly 
separated  thin  beds  and  layers  of  gray  sandstone,  altogether  750  to  800  feet 
in  thickness. 

No.  5  (24),  20  feet. — Conglomerate  and  some  red  clays. 

No.  6  (23),  40  feet. — Whitish  sandstone — forms  crest  of  hill  about  220 
to  240  feet  in  height. 

No.  7  (22),  110  feet. — Brownish  clays  and  beds  of  sandstone,  the  latter 
light  gray  below. 

No.  8  (21),  60  feet. — Brownish  clays  and  sandy  layers. 

No.  9  (20),  40  feet. — Greenish  white  sandstone. 

No.  10  (19),  600  feet. — Slope  showing  above  some  masses  of  con- 
glomerate, like  that  of  division  18,  perhaps  not  in  place,  with,  at  places  below 
this,  some  reddish  clays;  altogether  space  enough  for  500  to  600  feet  in 
thickness. 


SULPHER  CEEBK  SECTION,  BY  PROFESSOR  MEEK.  159 

No.  11  (18),  40  feet. — Hard  gray  conglomerate,  standing  nearly  ver- 
tical, and  forming  crest  of  hill  abput  350  feet  high. 

SALT    WELLS    GROUP. 

No.  12  (17),  115  feet. — Brownish  and  bluish  clays,  with  some  beds  of 
white,  greenish,  and  brownish  sandstones. 

No.  13  (16),  45  feet. — Clays  and  sandstone  below,  (20  feet),  and  gray 
and  brown  pebbly  sandstone  above,  (25  feet). 

No.  14  (15),  125  feet, — Bluish  laminated  clays,  with,  at  top  (left  or 
west  side),  a  two-foot  layer  of  sandstone,  containing  fragments  of  shells  not 
seen  in  a  condition  to  be  determined. 

No.  15  (14),  40  feet. — Ferruginous  sandstone  in  thin  layers,  dipping 
northwest  about  80°  below  horizon. 

No.  16  (13). — A  valley  or  depression  showing  no  rocks,  perhaps  150 
yards  across. 

No.  17  (12),  150  feet. — Light  gray  sandstones  and  clays,  including  a 
bed  of  good  coal,  said  to  be  7J  feet  in  thickness;  all  dipping  south-south- 
east 55°  below  horizon,  and  the  sandstone  above  the  coal  containing  many 
casts,  Inoceramus  problematicus,  with  a  few  casts  of  Cardium  and  undeter- 
mined univalves;  altogether  showing  about  150  feet. 

No.  18  (11). — Slope  and  unexposed  space,  perhaps  200  yards  or  more 
across. 
.     No.  19  (10),  20  feet. — Light  gray  sandstone. 

No.  20  (9),  255  feet. — Gray  sandy  shales  with  alternations  of  sand- 
stone and  clays. 

No.  21  (8),  95  feet. — Heavy  massive  bed  of  light  colored  sandstone, 
about  90  feet  in  thickness,  standing  nearly  vertical,  with  some  3  to  5  feet  of 
sandy  clay  between  it  and  the  coal  of  division  7. 

No.  22  (7),  7  feet  6  inches. — Bed  of  good  coal,  said  to  be  7J  feet  in 
thickness. 

No.  23  (6),  100  feet. — Greenish  and  bluish  gray  sandy  clays,  with 
some  d.ark  shale  at  places. 

No.  24  (5),  100  feet— Two  or  three  rather  heavy  beds  of  light  yel- 
lowish gray  sandstone,  separated  by  clays,  probably  occupying  some  of  the 


160  GEOGRAPHIC  DISTRIBUTION. 

space  included  in  division  4.  Near  the  lower  part  two  layers  15  to  18  inches 
each,  of  sandstone,  containing  Ostrea  soleniscus,  Trapezium  micronema,  &c. 
Altogether  90  to  100  feet  or  more. 

No.  25  (4),  300  feet. — Covered  space,  probably  occupied  by  clays, 
but  showing  some  sandstone  that  may  or  may  not  be  in  place;  perhaps 
room  enough  for  250  to  300  feet. 

No.  26  (3),  90  feet. — Soft  light  grayish  sandstone,  nearly  vertical. 

SUMMIT  OF  SULPHUR  CEEEK  GROUP. 

No.  27  (2),  100  feet. — Slope  apparently  occupied  by  clays,  thickness 
"  perhaps  100  feet  or  more. 

No.  28  (1). — Black  shale,  only  seen  in  bottom  of  Sulphur  Creek,  thick- 
ness unknown. 


BLACK   BUTTE    QUARTZITE. 

Southwest  of  Black  Butte  Station  on  the  Union  Pacific  Railroad  there 
is  a  conspicuous  topographic  feature  known  as  Black  Butte.  It  is  carved 
from  beds  of  the  Point  of  Rocks  Group  and  is  crowned  with  a  dark  indurated 
and  exceedingly  tough  quartzite,  which,  in  the  distance,  has  the  appearance 
of  a  bed  of  extra vasated  material,  and  even  on  closer  examination  I  was 
deceived  by  its  apparent  similarity  to  some  rhyolites. 

Rocks  having  a  similar  appearance  and  structure  are  found  on  the  sum- 
mit of  Aspen  Mountain,  and  I  unhesitatingly  considered  the  latter  to  be 
quartzites;  but,  on  visiting  Black  Butte,  the  general  weathering  and  exceed- 
ingly dark  appearance  of  these  beds  created  the  impression  that  they  had 
been  extravasated,  though  hand  specimens  had  the  appearance  of  quartzite, 
and  I  left  the  field  with  many  doubts  as  to  their  nature.  Captain  Dutton 
has  since  made  sections  of  this  rock  and  examined  them  under  the  micro- 
scope and  pronounces  it  a  quartzite. 

Such  a  conclusion  in  connection  with  the  geological  relations  of  these 
beds  is  very  interesting  Quartzites,  from  geological  considerations  of 
structure  and  erosion,  are  usually  supposed  to  have  been  at  some  time  deep 
seated  and  are  often  shown  to  have  been  involved  in  profound  plication,  or 


THE  CENOZOIC  GROUPS.  161 

implication,  and  are  usually  considered  to  be  metamorphosed  sandstones,  the 
metamorphisin  due  to  deep  seated  agencies ;  but  this  quartzite  is  of  very  late 
Cretaceous  Age  or  may  even  belong  to  higher  unconformable  Tertiaries. 
In  either  case  the  same  strata  on  every  hand  are  soft,  comparatively  friable, 
granular  sandstones ;  they  are  immediately  underlaid  by  great  thicknesses  of 
sandstones  of  like  characteristics.  They  have  not  been  implicated  or  even 
plicated.  No  extravasated  material  is  found  in  the  immediate  vicinity  to 
which  reference  can  be  made  as  the  origin  of  crystallization,  and  these  beds 
on  Black  Butte  are  more  than  200  feet  in  thickness,  and  metamorphism  from 
contact  with  eruptive  rocks,  so  far  as  my  studies  extend  in  this  western  coun- 
try, is  exceedingly  slight,  and  indeed  such  slight  change  is  rarely  shown. 
There  is  nothing  in  the  surroundings  to  suggest  metamorphism. 

Is  it  possible  that  conditions  obtained  here  favorable  to  the  deposition 
of  silica  by  chemical  precipitation?  This  question  has  been  often  suggested 
by  facts  observed  at  many  other  places  in  the  Plateau  Province.  In  my 
remarks  on  the  Uinta  Group  I  mentioned  that  some  of  the  sandstones  were 
quasi  quartzites,  and  where  such  beds  of  quartzite  are  found  the  quartzite 
structure  is  invariably  local.  The  same  beds  traced  laterally  are  typical 
sandstones ;  and  above  and  below,  soft  sandstones  and  excessively  friable 
shales  are  found,  and  there  is  no  local  disturbance  of  these  beds.  They 
have  simply  been  displaced  in  the  grand  upheaval  in  common  with  the  sand- 
stones and  shales;  and  if  this  lithologic  characteristic  is  due  to  conditions  of 
deposition  and  have  not  been  imposed  by  the  agencies  of  metamorphism,  at 
what  place  in  the  table  of  sedimentary  groups  shall  we  begin  to  consider 
quartzites  to  be  products  of  metamorphism?  At  Black  Butte  the  quartzite 
is  as  high  at  least  as  the  very  summit  of  the  Cretaceous;  in  the  Uinta  Mount- 
ains the  quartzites  are  low  down  in  the  Paleozoic  series  and  these  are  sepa- 
rated by  nearly  30,000  feet  of  sedimentary  accumulations.  May  we  go  one 
foot  farther  down  in  the  rocks,  but  across  the  great  gap  of  unconformity,  and 
say  that  the  Red  Creek  quartzites  were  such  from  original  constitution? 

THE  CENOZOIC  GROUPS. 

This  description  of  the  geographic  distribution  of  the  Cenozoic  Groups 
will  be  confined  to  the  region  north  of  the  Uinta  Mountains,  except  in  the 
11   P  G 


162  GEOGRAPHIC  DISTRIBUTION. 

case  of  the  Brown's  Park  Group  and  the  Bishop  Mountain  Conglomerate. 
A  small  strip  of  country  on  the  south  side  of  the  mountains  has  been  given 
a  Tertiary  color  on  the  map  for  the  purpose  of  presenting  an  interesting 
fact  in  the  relation  of  the  groups  of  that  region  ;  but  this  is  only  the  border 
of  a  broad  area  through  which  Ceriozoic  formations  are  distributed,  and  to 
discuss  this  border  with  clearness  it  is  necessary  to  enter  into  a  consideration 
of  the  whole  area,  which  can  be  done  much  better  when  we  have  the  map 
of  that  country  before  us. 

In  the  Uinta  and  White  River  basins,  south  of  the  Uinta  Mountains, 
where  these  Tertiaries  have  a  great  development,  the  lower  formations  of 
this  Age  have  been  pretty  thoroughly  worked  out,  but  there  are  higher  beds 
not  so  well  understood. 

I  now  turn  to  a  consideration  of  the  country  north  of  the  Uinta  Moun- 
tains. 

BITTER    CREEK    GROUP. 

Here  the  Bitter  Creek  beds  have  an  extensive  exposure  on  the  flank  of 
the  Uinta  upheaval  and  on  either  flank  of  the  Aspen  Mountain  uplift. 

In  the  Flaming  Gorge  district,  west  of  the  Green  River,  the  beds  of 
this  group  rapidly  attenuate  until  they  disappear,  and  here  their  lithologic 
character  is  changed,  as  the  fine  grained  friable  sandstones  are  replaced  by 
conglomerates ;  and  as  the  beds  here  are  dipping  at  a  great  angle  to  the 
north,  so  that  their  upturned  edges  are  well  exposed,  the  harder  conglomer- 
ates are  seen  to  stand  in  high  ledges  and  walls.  Eastward  from  the  Green 
River  the  beds  rapidly  thicken  until,  at  Richard's  Peak  and  Quien  Hornet 
Mountain,  a  section  of  more  than  5,000  feet  is  presented,  and  here  at  the 
base  we  have  a  great  development  of  conglomerates.  Richard's  Peak  itself 
is  a  monoclinal  ridge  of  this  conglomerate. 

The  disappearance  of  these  beds  by  attenuation  on  the  west  side  of  the 
Green  River  and  their  increase  above  the  normal  thickness  east  of  that 
stream,  together  with  the  change  in  their  lithologic  constitution,  leads  us  to 
infer  that  we  here  have  the  beds  exposed  near  the  old  shore  line  that  was 
established  by  the  upheaval  of  the  Uinta  Mountain  region.  Conglomerates 
are  found  at  the  base  of  the  group  in  many  places  on  the  north  side  of  the 
Uintas,  and  I  suppose  the  conglomerates  on  the  west  side  of  the  Green 


THE  CENOZOIC  GROUPS.  163 

River  to  be  at  the  same  horizon,  namely,  at  the  base  of  the  series,  and  that 
the  attenuation  is  due  to  the  non-deposition  of  the  upper  beds  over  the  area 
here  brought  to  light,  Of  this,  conclusive  evidence  was  not  obtained,  and 
it  may  possibly  be  that  these  conglomerates  represent  higher  beds  which, 
farther  from  the  shore,  were  sandstones  of  more  thoroughly  comminuted 
material.  But,  while  I  suggest  this  possible  explanation,  I  am  inclined  to 
consider  them  as  belonging  to  the  lower  members  of  the  group,  and  that 
after  their  deposition  the  area  was  left  as  dry  land,  while  the  sands  were 
accumulating  in  the  bed  of  the  lake  farther  from  the  axis  of  upheaval. 

From  the  Green  River  eastward,  nearly  to  the  foot  of  Richard's  Peak, 
the  base  of  the  group  is  composed  of  bad-land  sandstones  with  more  indu- 
rated beds  intercalated ;  the  latter  are  usually  light  gray,  sometimes  quite 
white ;  the  former  are  exceedingly  ferruginous  and  sometimes  shaly;  but 
from  the  western  base  of  Richard's  Peak,  nearly  to  the  outcrop  of  the  Red 
Wall  limestone,  conglomerates  are  found,  and  here  the  whole  thickness  of 
the  group  is  much  increased.  It  is  interesting  to  notice  that  these  con- 
glomerates are  found  opposite  the  outcrop  of  the  Red  Creek  Quartzite. 
But  the  materials  of  which  the  conglomerates  are  composed  seem  not  to 
have  been  derived  from  the  quartzite,  if  I  may  trust  my  notes :  and  I  should 
here  state  that  the  geographic  relation  between  the  quartzite  and  the  con- 
glomerate did  not  occur  to  me  while  in  the  field,  and  in  my  notes  on  the 
conglomerate  I  have  mentioned  that  its  bowlders  are  sandstones  and  lime- 
stones, and  that  some  of  the  latter  contain  Jurassic  fossils;  but  I  have 
recorded  observations  at  only  two  points — one  at  Richard's  Peak,  the  other 
at  Bruce  Mountain.  With  the  facts  now  at  my  command  I  am  inclined  to 
think  that  when  this  conglomerate  was  formed,  erosion  had  not  progressed 
through  the  Carboniferous  groups  and  Uinta  Sandstone  so  as  to  reach  the 
quartzite  on  the  upheaved  side,  but  that  the  conglomerate  is  composed  of 
sandstones  from  the  Cretaceous  groups,  and  limestones  and  sandstones  of 
the  Jura  Trias,  and  possibly,  to  some  extent,  from  Carboniferous  beds.  It 
would  seem  that  the  appearance  of  the  conglomerate  here  is  to  be  explained 
by  geographic,  rather  than  by  geological,  considerations — that  is,  the  line  of 
exposure  of  the  base  of  the  group  in  this  region  is  near  to  the  old  shore 
line ;  for  it  is  manifest  that  here  was  a  headland  projecting  from  the  Uinta 


164  GEOGRAPHIC  DISTRIBUTION. 

region  into  the  old  Bitter  Creek  lake,  while  westward,  from  'Richard's  Peak 
to  the  Green  River,  the  present  exposure  of  the  strata  is  across  the  bed  of 
an  ancient  bay.  • 

West  from  Richard's  Peak  the  plane  of  separation  between  the  Bitter 
Creek  and  Point  of  Rocks  Groups  is  masked  to  a  greater  or  less  extent  on 
account  of  the  exceeding  friability  of  the  lower  beds  of  Bitter  Ci'eek  age ; 
still  careful  examination  reveals  the  fact  that  they  are  unconformable,  and 
this  unconformity  is  very  clearly  exhibited  at  the  eastern  end  of  the  mono- 
clinal  ridge,  composed  of  the  Upper  Hogback  Sandstone  of  the  Point  of 
Rocks  Group,  near  the  foot  of  Richard's  Peak,  in  an  amphitheater  of  erosion 
at  the  head  of  a  dry  gulch. 

Between  the  western  end  of  the  outcrop  of  Red  Wall  limestone  on  the 
northwest  end  of  the  0-wi-yu-kuts  Plateau  and  the  Po  Canon  district  the 
base  of  the  Bitter  Creek  series  is  not  seen,  as  it  has  been  carried  down  by 
the  fault.  On  the  north  side  of  Diamond  Peak  the  Bitter  Creek  beds  are 
lying  horizontal,  and,  studying  this  mountain  from  that  side,  it  would  seem 
to  be  composed  of  Bitter  Creek  beds,  perhaps  capped  by  beds  of  the  Lower 
Green  River,  but  on  climbing  the  mountain  its  summit  is  seen  to  be  composed 
of  angular  fragments  of  sandstones  piled  in  an  indiscriminate  manner,  the 
age  of  which  was  not  fully  determined ;  descending  it  on  the  south  side 
this  same  confusion  is  observed.  Of  what  the  principal  mass  of  this  peak 
is  composed  I  do  not  know. 

In  the  Po  Canon  district  along  the  channel  of  Vermilion  Creek  and 
many  of  its  lateral  tributaries,  deep  corrasion  has  produced  many  steep 
escarpments  of  the  Bitter  Creek  beds.  Here  we  find  the  Point  of  Rocks 
Group  standingon  edge,  and  near  by,  and  separated  from  the  former  only 
by  narrow  gulches,  Bitter  Creek  beds  of  a  horizon  about  midway  in  the 
group  are  found  lying  hoiizontally;  but  in  a  few  places  lower  beds  of  the 
Bitter  Creek  series  are  turned  up  on  edge  with  the  Point  of  Rocks  beds  and 
the  middle  beds  of  the  Bitter  Creek  Group  lie  over  their  upturned  and  eroded 
edges  unconformably,  and  over  some  of  the  upper  beds  of  the  Point  of  Rocks 
Group  in  like  manner.  Thus  the  middle  beds  of  the  Bitter  Creek  overlap 
the  lower  beds,  not  because  they  were  deposited  over  a  broader  area,  but 
because  the  lower  beds  in  a  part  of  their  extent  were  exposed  to  erosion  and 


THE  CENOZOIC  GEOUPS.  165 

carried  away  prior  to  the  deposition  of  the  middle  beds.  These  facts  are 
illustrated  in  Fig.  15.  I  do  not  think  that  the  base  of  the  Bitter  Creek  series 
is  found  exposed  in  this  vicinity.  The  displacement  here  has  evidently  been 
exceedingly  complex,  and  its  study  is  rendered  difficult  by  unconformities, 
and  it  is  not  always  easy  to  determine  to  which  class  of  agencies  certain 


500  2000  1500     £*  NoTtll 


B.  C.  Bitter  Creek  Group.    P.  E.  Point  of  Rocks  Group. 
Fig.  15. 

phenomena  are  due.  In  some  portions  of  the  line  of  displacement  the  beds 
are  marked  by  certain  late  Tertiaries  of  Brown's  Park  age  as  will  be  more 
fully  explained  hereafter. 

West  of  Bishop  Mountain,  stretching  across  the  many  tributaries  of  the 
Vermilion,  there  is  a  broad  expanse  of  country  where  the  beds  of  this  age 
are  exposed  in  naked  bad-land  hills,  and  on  either  flank  of  the  Aspen  Mount- 
ain uplift  they  are  seen  usually  forming  regions  sterile  and  desolate. 

At  the  head  of  Little  Bitter  Creek  there  is  a  stretch  of  table  land  where 
beds  of  Bishop  Mountain  Conglomerate  are  found.  In  the  late  redistribu- 
tion of  this  conglomerate  its  materials  have  been  carried  quite  over  the  line 
separating  the  Bitter  Creek  from  the  Point  of  Rocks  Group,  so  that  the 
junction  is  completely  masked,  but  in  the  escarpment  south  of  the  plateau 
which  faces  Quien  Hornet  Mountain  the  junction  is  well  revealed  ;  and  the 
same  is  true  farther  to  the  north  in  lateral  canons  along  the  upper  course  of 
Little  Bitter  Creek.  The  conglomerates  found  at  the  base  of  the  series  on 
the  flank  of  the  Uintas  are  not  seen  on  the  flanks  of  the  Aspen  Mountain 
uplift,  and  the  Bitter  Creek  beds  attenuate  toward  the  north.  From  these 

• 

facts  I  infer  that  the  materials  of  the  Bitter  Creek  Group  were  derived  in 
large  part  at  least  from  the  Uinta  region,  that  is  that  the  bad-land  rocks 
of  Mesozoic  Age  •  were  carried  from  the  Uinta  region  and  redistributed  as 
bad-land  beds  of  the  Bitter  Creek  period. 

In  this  great  fresh  water  basin  conditions  favorable  to  the  deposition  of 


166  GEOGRAPHIC  DISTRIBUTION. 

carbonaceous  shales  and  lignitic  coal  obtained  from  time  to  time,  now  here 
now  there,  and  such  shales  and  coals  are  found  distributed  in  great  profu- 
sion throughout  the  entire  area  which  has  been  studied.  In  a  section  made 
on  the  south  side  of  the  railroad  between  Lawrence  Section  House  and  Rock 
Springs  more  than  30  seams  and  beds  of  coal  are  noted.  The  coals  of  this 
horizon  in  the  vicinity  of  Black  Butte  Station  have  been  frequently  described 
by  other  geologists. 

It  is  not  my  purpose  to  discuss  the  distribution  and  character  of  the 
lignitic  coals  in  this  report. 

LOWER    GREEN   RIVER    GROUP. 

In  the  Flaming  Gorge  district  the  Lower  Green  River  Group  overlaps 
the  Bitter  Creek  Group,  and  farther  westward  disappears  by  attenuation. 

The  course  of  the  Green  River  from  the  northern  border  of  the  area 
embraced  on  the  map  to  the  hogback  six  miles  north  of  Flaming  Gorge  is 
through  the  beds  of  this  group,  and  an  irregular  escarpment  of  these  beds 
having  deep  reentrant  angles,  and  spaces  broken  into  low  hills,  faces  the 
axis  of  the  Aspen  Mountain  uplift.  The  escarpment  known  as  Pine  Bluffs 
on  the  east  side  of  the  uplift  is  of  this  age.  Another  outcrop  is  found  north 
of  Dry  Mountains  and  west  of  the  Po  Canon  district,  where  their  upturned 
edges  are  exposed  on  the  border  of  a  basin  of  displacement  or  sag  due  to  a 
downthrow. 

This  group  is  composed  chiefly  of  bituminous  shales  and  impure  lime- 
stones, the  latter  being  both  arenaceous  and  argillaceous;  but  to  the  south, 
near  the  Uinta  uplift,  the  group  is  much  thickened  and  the  shales  are  replaced 
by  sandstones,  and  conglomerates  of  fine  pebbles  appear. 

From  this  fact  it  is  inferred  that  the  beds  of  this  group  are  derived  from 
the  Uinta  region,  and  that  the  material  was  supplied  from  limestones  and 
sandstones  of  Carboniferous  Age.  Conditions  favorable  to  the  accumula- 
tion of  Carbonaceous  shales  and  lignitic  coal  are  less  frequent  than  in  the 
former  period,  but  a  fine  bed  of  coal  has  been  found  at  the  base  of  this  group 
on  the  bank  of  the  Green  River,  about  eight  miles  below  the  station,  and 
Carbonaceous  shales  and  thin  seams  of  coal  have  been  found  at  other  hori- 
zons elsewhere. 


THE  CENOZOIC  GROUPS.  167 


UPPER    GREEN    RIVER    GROUP. 

^JVI4 

The  beds  of  this  group  are  well  exposed  in  high  escarpments  on  either 
side  of  the  Green  River  from  the  northern  boundary  of  the  district  embraced 
on  the  map  nearly  to  the  hogback  six  miles  above  Flaming  Gorge,  and  they 
stretch  in  a  continuous  but  irregular  belt  on  the  west  side  of  that  stream  for 
the  same  distance,  and  are  exposed  on  Henry's  Fork  for  many  miles. 

On  the  east  side  of  the  Green  River  they  are  found  in  outlying  discon- 
nected patches.  The  most  important  of  the  latter  are  colored  on  the  map. 
They  are  also  seen  in  the  district  east  of  Po  Canon  with  their  edges  upturned 
around  the  basin  of  displacement  previously  mentioned.  It  is  probable 
that  these  beds  are  also  found  east  of  Pine  Bluffs,  but  when  that  country 
was  studied  in  1868,  I  had  not  separated  the  Upper  from  the  Lower  Green 
River  beds,  and  not  having  visited  the  country  since,  I  am  not  prepared  to 
give  any  facts  concerning  the  matter. 

In  a  former  chapter  I  stated  that  the  Upper  Green  River  beds  were 
interpolated  between  Bridger  and  Lower  Green  River  only  through  a  por- 
tion of  the  great  Tertiary  basin  north  of  the  Uinta  Mountains.  These  beds 
have  their  greatest  development  in  the  region  about  Green  River  Station, 
extending  for  20  or  30  miles  to  the  north  and  south,  and  it  is  probable  that 
the  material  of  which  they  are  composed  was  derived  in  part,  at  least,  from 
other  than  the  Uinta  region,  though  doubtless  this  region  yielded  a  share 
of  the  detrital  matter.  Carbonaceous  shales  and  lignitic  coal  are  found  at 
this  horizon  on  Henry's  Fork.  Two  of  the  coal  beds  have  been  explored 
and  when  tested  are  said  to  have  yielded  fair  coals. 

I  have  already  in  a  former  chapter  described  the  Tower  Sandstone  at 
the  base  of  this  group,  and  explained  the  nature  of  the  unconformity  between 
the  Upper  and  Lower  Green  River  Groups. 

BRIDGER   GROUP. 

The  Bridger  beds  are  found  outcropping  on  the  western  border  of  the 
district  under  discussion  north  of  Henry's  Fork,  and  again  to  the  east  of  the 
Po  Canon  district  in  the  sag  of  displacement  north  of  the  Dry  Mountains. 

No  unconformity  has  been  discovered  between  the  Bridger  and  Upper 


168  GEOGRAPHIC  DISTRIBUTION. 

Green  River,  and  the  plane  of  demarkation  is  obscure,  or  rather  there  is  no 
plane  of  demarkation,  but  the  separation  is  transitional;  but  the  bad-land 
beds  of  the  Bridger  Group  are  very  distinct  from  the  limestones  and  sand- 
stones of  the  Upper  Green  River.  In  the  latter,  sandstones  usually  rather 
massive,  and  in  the  case  of  the  Tower  Sandstone  greatly  so,  have  impure 
limestones  intercalated.  In  the  former,  bad-land  sandstones  prevail,  and  these 
are  largely  green  sands,  but  irregular  beds  and  aggregations  of  chalcedony 
are  abundant,  and  high  in  the  series  two  well  marked  andr  persistent  lime- 
stones are  found.  These  beds  of  chalcedony  afford  the  moss  agates  for 
which  the  region  about  Fort  Bridger  has  been  noted.  I  suppose  them  to 
have  been  deposited  by  chemical  precipitation  from  waters  highly  charged 
with  silica.  The  limestones  are  in  many  places  crypto-crystalline,  and  break 
with  a  conchoidal  fracture  and  often  have  the  ring  of  phonolite.  I  consider 
these  also  to  be  chemical  precipitates.  Fresh  water  fossils  are  sometimes 
found  imbedded  in  the  crystalline  masses,  but  can  rarely  be  obtained  in  a 
perfect  state,  but  fossils  are  more  abundant  in  the  arenaceous  and  argilla- 
ceous partings,  and  can  be  obtained  in  a  good  state  of  preservation.  In  the 
green  sands  vertebrate  fossils  have  been  found  in  abundance,  and  concern- 
ing them  much  has  already  been  written  by  eminent  paleontologists. 
No  coal  has  been  discovered  in  the  Bridger  Group. 

BROWN'S  PARK  GROUP. 

These  beds  are  found  in  the  valley  known  as  Brown's  Park  and  a  dis- 
trict of  country  stretching  thence  to  the  southwest  beyond  the  Snake  and 
Yampa  Rivers.  In  Brown's  Park  they  lie  in  a  deep  basin  of  erosion,  the 
bottom  and  sides  of  which  are  composed  of  Uinta  Sandstone.  This  basin 
is  in  the  very  axis  of  the  Uinta  uplift.  Eastward,  both  on  the  north  and 
south  sides  of  the  area  of  outcrop,  the  beds  are  seen  to  rest  unconformably 
upon  all  of  the  Carboniferous,  Mesozoic,  and  Cenozoic  formations  previously 
mentioned.  Its  unconformity  with  the  Upper  Green  River,  Lower  Green 
River,  and  Bridger  beds  is  well  exhibited  in  the  Dry  Mountains  in  many 
fine  exposures.  Its  structural  relations  to  these  beds  will  be  discussed  here- 
after. Its  sandstones  are  bad-land  rocks  of  exceedingly  fine  texture.  In 


THE  CENOZOIO  GKOUPS. 

some  places  these  rocks  are  composed  of  thin  laminae  of  many  delicate 
colors,  but  they  do  not  readily  part  along  the  planes  of  stratification,  but 
crumble  easily  and  often  break  in  large  masses.  Extensive  beds  and  irregu- 
lar aggregations  of  chalcedony  are  found  and  I  suppose  them  to  have  been 
deposited  by  precipitation.  Conglomerates  are  found,  at  the  base,  in  some 
localities  having  a  great  development.  The  beds  incline  slightly  from  the 
wall  of  the  park  on  the  south  side ;  this  inclination  may  be  due  to  the  bottom 
on  which  they  were  deposited.-  On  the  north  side  the  beds  are  turned  up  at 
a  great  angle,  showing  much  displacement  since  they  were  deposited,  and 
immediately  outside  of  the  irregular  line  of  outcrop  a  fault  has  been  observed 
with  its  throw  to  the  south. 

In  Brown's  Park  the  streams  which  come  down  from  the  mountains  on 
either  side  have  in  many  places  cut  through  these  beds  and  reveal  in  the 
depths  of  their  channels  the  old  floor  of  Uinta  Sandstone.  But  a  few  hun- 
dred feet  of  these  beds  are  left  in  Brown's  Park,  but  eastward  a  much  greater 
thickness  remains  preserved  from  denudation.  It  is  probable  also  that  this 
greater  thickness  is  due  in  part  to  greater  sedimentation. 

In  the  northeast  portion  of  the  Po  Canon  district  there  is  another  out- 
crop of  this  group.  Here  the  beds  rest  unconformably.  on  the  Uinta  Sand- 
stone, the  several  Carboniferous  groups,  the  several  Mesozoic  groups,  on 
Bitter  Creek  beds,  and  also  on  the  heterogeneous  mass  of  sandstones  of 
which  Diamond  Peak  is  composed. 

BISHOP    MOUNTAIN    CONGLOMERATE. 

This  conglomerate  is  found  only  in  isolated  patches  as  remnants  adven- 
titiously preserved  from  the  general  erosion  to  which  this  widely  spread 
formation  has  been  subjected. 

An  outlying  patch  or  fragment  is  found  on  the  north  side  of  Sage  Creek 
overlying  unconformably  the  beds  of  Lower  Green  River  age.  Another  is 
found  on  the  plateau  where  Sage,  Little  Bitter,  and  Pretty  Creeks  have  their 
sources;  here  the  conglomerate  rests  on  Point  of  Rocks  beds.  Another  is 
found  on  the  summit  of  Quien  Hornet  Mountain  resting  on  Lower  Green 
River  beds.  Another  is  found  on  Bishop  Mountain  resting  on  Bitter  Creek 
beds.  On  the  south  side  of  the  Uinta  Mountains  a  fragment  is  found  west 


170  GEOGRAPHIC  DISTRIBUTION. 

of  Echo  Park  resting  on  Carboniferous  beds.  Another  fragment  is  found  ten 
or  twelve  miles  west  of  the  Canon  of  Lodore  resting  on  Carboniferous  and  Jura 
Trias  beds.  A  fragment  is  found  west  of  Brush  Creek  also  lying  on  the  Car- 
boniferous and  Jura  Trias  beds;  and  the  Wa-ka-ri-chits  are  capped  with  this 
conglomerate,  which  here  rests  on  Sulphur  Creek  beds. 

These  are  the  only  fragments  which  I  have  discovered  in  the  area  em- 
braced on  the  map,  but  to  the  westward,  on  both  flanks  of  the  Uinta  uplift, 
this  formation  has  a  much  more  extensive  geographic  development  and  it  is 
also  found  in  greater  thickness.  On  the  north  side  of  Connor  Basin,  at  the 
head  of  Sheep  Creek,  this  conglomerate  has  a  thickness  of  more  than  a  thou- 
sand feet. 

There  are  some  conglomerates  on  the  peaks  of  the  Dry  Mountains 
which  at  one  time  I  believed  to  belong  to  this  period,  but  I  now  think  they 
are  of  the  Brown's  Park  age. 

In  the  destruction  arid  redistribution  of  this  formation,  the  materials  of 
which  it  was  composed  have  been  scattered  in  many  places  here  and  there 
on  either  flank  of  the  Uinta  uplift.  The  conglomerate  is  composed  of  bowl- 
ders and  pebbles  of  sandstone,  quartzite  and  crystalline  schists,  but  sand- 
stones and  quasi  quartzites  probably  of  the  Uinta  period  greatly  prevail; 
but  in  the  original  beds  and  redistributed  materials  found  so  abundant  north 
and  northeast  of  Mount  Wheeler  where  the  Red  Creek  Quartzite  is  exposed, 
white  quartz  and  crystalline  schists  are  far  more  abundant  than  elsewhere. 
Sometimes  at  least  the  cement  is  calcareous.  In  the  fragment  west  of  Echo 
Park  large  and  somewhat  angular  blocks  of  Uinta  Sandstone  are  found. 

I  think  that  many  geologists  would  ascribe  this  conglomerate  to  the 
action  of  ice,  but  throughout  all  that  portion  pf  the  Rocky  Mountain  region 
which  I  have  studied,  I  have  so  frequently  found  gravels  and  conglomer- 
ates of  sub-aerial  origin,  and  have  in  so  many  cases  found  reason  to  change 
my  opinion  concerning  them,  often  having  attributed  a  drift  like  deposit  to 
glacial  action,  and*afterward  on  further  study  abandoned  the  theory,  being 
able  to  demonstrate  its  sub-aerial  origin,  and  witnessing  on  every  hand  the 
accumulation  of  such  gravels  in  valleys  and  over  plains  where  mountains 
rise  to  higher  altitudes  on  either  side,  and  having  in  many  cases  actually 
seen  the  cliffs  breaking  down  and  the  graveb  rolling  out  on  the  floods  of  a 


THE  CENOZOIO  GKOUPS.  171 

storm,  I  am  not  willing1  to  disregard  explanations  so  obvious  and  so  certain 
for  an  extraordinary  and  more  violent  hypothesis. 

Irregular  accumulations  of  clay,  accumulations  of  sand,  of  gravels,  and 
bowlders  having  in  a  general  way  all  the  lithologic  characteristics  of  "drift" 
are  very  common  in  the  Rocky  Mountain  region,  and  in  many  cases  I  am 
convinced  that  their  origin  can  be  traced  to  ordinary  atmospheric  agencies 
acting  on  the  adjacent  hills  and  mountains;  and  no  glaciers  or  icebergs  are 
needed  for  their  explanation. 

Nor  need  the  thickness  and  extent  of  this  Bishop  Mountain  Conglomer- 
ate serve  to  weaken  this  explanation,  for  the  sub-aerial  gravels  in  the  valleys 
between  the  ranges  in  the  Basin  Province  are  of  equal  and  often  of  greater 
development.  Whenever  a  low  plain,  valley  or  basin  is  for  a  comparatively 
long  period  but  little  elevated  above  the  base  level  of  erosion,  and  during 
this  time  mountains  and  hills  stand  about  the  lowlands,  there  must  be  a  great 
accumulation  of  drift,  and  where  the  highlands  are  areas  of  progressive  ele- 
vation and  the  lowlands  areas  of  progressive  subsidence  this  accumulation 
may  continue  indefinitely. 

Thus  it  is  that  I  attribute  the  drift  of  the  Rocky  Mountain  region  to 
sub-aerial  agencies,  chiefly  the  action  of  rains  and  streams.  Mountains  are 
not  degraded  by  the  slow  washing  down  of  their  surfaces  but  they  are  dug 
down  by  the  corrasion  of  deep  channels  and  the  undermining  of  ledges  and 
cliffs,  and  the  materials  thus  loosened  from  the  great  rock  masses  to  which 
they  originally  belonged  are  carried  down  to  the  lowlands  by  storms.  In 
one  hour  of  storm  more  material  is  carried  to  the  lowlands  than  in  days, 
weeks,  or  months  when  the  mountain  streams  are  clear  brooks.  Yet  there 
has  been  glacial  action  in  the  Uinta  Mountains,  for  there  are  found  undoubted 

MORAINAL   DEPOSITS. 

* 

The  deep  valleys  that  lie  at  the  feet  of  the  axial  peaks  of  this  great 
range  have  been  beds  of  now  extinct  glaciers.  Morainal  deposits,  roches 
moutonneeSj  glaciated  grooves,  and  morainal  lakelets  are  found  in  very 
many  of  these  elevated  valleys.  Often  the  valleys  are  so  choked  with  the 
materials  thus  accumulated  by  the  action  of  ice  that  travel  across  them  is  of 
great  difficulty.  From  the  crevices  between  these  ice  piled  rocks  high  pine? 


172  GEOGRAPHIC  DISTKIBUTION. 

and  firs  are  growing,  and  hundreds,  thousands  of  little  basins  filled  with 
clear,  cold  water  are  found.  These  glacial  deposits  are  doubtless  of  much 
later  origin  than  the  Bishop  Mountains-Conglomerate;  often  they  are  min- 
gled with  and  masked  by  drift  which  has  been  brought  down  from  the 
heights  by  storms,  and  in  many  places  it  is  impossible  to  separate  that  which 
is  due  to  this  latter  agency  from  that  which  is  due  to  the  agency  of  ice;  and 
as  you  descend  the  valleys  away  from  the  peaks  where  the  glacial  snow  was 
accumulated  the  mingling  of  the  two  increases  by  an  increase  in  the  amount 
of  drift  until  at  last  the  glacial  formation  is  lost  and  drift  only  appears ;  taken 
throughout  the  Uinta  Mountains,  the  glacial  material  is  far  less  in  quantity 
than  the  drift  material.  What  I  have  thus  described  as  glacial  action  is 
exceptional  or  local  and  trivial  as  compared  with  drift  agencies,  which  must 
always  obtain  in  mountain  regions  alike  when  they  are  free  from  glaciers  or 
when  the  elevated  valleys  are  filled  with  ice. 

Thus  the  glacial  epoch  in  the  Uinta  Mountains  was  doubtless  a  reality; 
the  evidences  of  such  a  time  are  abundant,  but  they  are  found  only  high  up 
on  the  range,  and  the  gravels  and  bowlders  of  the  lowlands  attest  only  to 
the  ordinary  action  of  drift  agencies.  I  may  remark  here  that  the  evidences 
of  the  same  glacial  epoch  are  abundant  in  the  Park  Mountains;  but  there 
also  the  glaciers  were  confined  to  the  elevated  ranges.  The  gravel  beds  on 
the  lowlands  are  true  drift. 

LIGNITIC  COAL. 

But  little  reference  has  been  made  to  the  lignitic  coals  found  in  the 
Uinta  region;  it  is  expected  that  the  coals  of  the  Plateau  Province  will  be 
discussed  in  a  separate  volume. 


CHAPTER 


STRUCTURAL  GEOLOGY. 

In  the  preceding  chapters  many  of  the  facts  relating  to  the  structural 
geology  of  the  region  under  discussion  have  been  presented,  but  they  were 
given  only  to  serve  purposes  relating  to  the  subjects  of  which  I  was  then 
treating.  In  the  first  chapter  it  was  necessary  to  refer  to  this  region  in 
characterizing  the  three  provinces;  in  the  second,  other  facts  were  presented 
in  explanation  of  the  grouping  of  the  sedimentary  rocks;  and  in  the  fourth, 
still  other  facts  were  given  in  discussing  geographic  distribution.  I  now  pro- 
pose to  assemble  these  facts  with  others  relating  to  structural  geology,  for 
the  purpose  of  more  clearly  setting  forth  the  geological  structure  of  the 
Uinta  Mountains,  Yampa  Plateau,  Junction  Mountain,  Diamond  Peak,  the 
Dry  Mountains,  Brown's  Park,  and  the  Aspen  Mountain  district  in  the  order 
thus  indicated. 

DESCRIPTION    OF    ILLUSTKATIONS. 

For  the  purpose  of  more  clearly  setting  forth  these  facts  certain  illus- 
trations have  been  prepared  and  will  be  found  in  the  atlas. 

Structure  Sections. — On  Plate  I  is  grouped  a  series  of  sections  through 
the  Uinta  Mountains,  from  south  to  north,  and  six  miles  apart.  In  each 
section  the  structure  observed  has  been  projected  below  the  line  of  sight 
to  the  level  of  the  sea,  that  the  facts  observed  might  be  represented  in  a 
more  graphic  manner.  This  hypothetic  projection  represents  the  most  prob- 
able condition  of  underground  structure  to  that  depth,  yet  there  may  be 
unconformities  unknown  to  us  and  of  which  no  hint  is  given  in  the  stra- 
tigraphy at  the  surface  or  in  the  structural'  geology .  of  the  surrounding 
country ;  but  from  the  absence  of  these  indications,  such  unconformities 
are  rendered  improbable. 

As  the  Uinta  upheaval  began  at  the  close  of  the  Point  of  Rocks  period, 


173 


174  STRUCTURAL  GEOLOGY. 

this  gives  us  a  datum  point  from  which  to  measure  displacement,  degrada- 
tion in  the  region  of  uplift,  and  sedimentation  in  the  region  of  downthrow. 
For  this  reason  the  group  is  graphically  accented  in  each  section. 

Displacement  Diagrams. — On  Plate  II  is  grouped  a  series  of  diagrams 
designed  to  represent  displacement  and  degradation.  Each  diagram  corre- 
sponds to  and  is  derived  from  a  section  in  Plate  I,  and  is  composed  of  three 
lines:  the  sea  level  line  and  the  surface  line,  which  are  the  same  as  those  in 
the  corresponding  section,  and  a  third,  a  displacement  line,  which  is  the 
accented  line  of  the  section,  projected  in  the  region  of  uplift  from  the  observed 
outcrop  of  the  group  which  it  represents  (Point  of  Rocks  Group),  to  the 
position  it  would  have  in  the  section  had  there  been  no  degradation  but 
displacement  only. 

We  thus  take  the  sea  level  as  the  zero  from  which  to  measure  displace- 
ment; and  by  introducing  the  surface  line,  the  accented  line  above  becomes 
a  zero  for  the  measurement  of  degradation  in  the  region  of  uplift;  and  as 
this  accented  line  represents  the  position  of  the  last  bed  deposited  prior  to 
the  inception  of  the  upheaval  (which  is  the  highest  Cretaceous  bed),  it  also 
forms  a  zero  line  from  which  to  measure  the  sedimentation  on  the  flanks  of 
the  upheaval  which  occurred  subsequent  to  the  inception  of  the  displace- 
ment; or,  in  other  words,  a  zero  line  from  which  to  measure  Post-Cretaceous 
sedimentation.  Hence  in  the  region  of  downthrow,  with  the  accented  line 
as  the  zero,  the  surface  line  measures  the  amount  of  Post-Cretaceous  sedi- 
mentation, minus  an  unknown  loss  by  degradation. 

It  may  be  well  here  to  explain  the  method  by  which  the  position  of  the 
displacement  line  was  determined.  In  the  topographic  survey  the  altitude 
of  many  points  on  the  surface  is  fixed  with  a  reasonable  approximation^ 
accuracy  by  the  use  of  the  barometer  and  theodolite.  These  points  are  the 
junction  of  drainage  lines,  the  summits  of  peaks,  and  many  other  salient 
and  conspicuous  topographic  features ;  and  from  these,  contour  lines  are 
drawn  by  inspection.  Hence  the  topographic  map  fixes  the  position  of  any 
bed  appealing  on  the  surface  with  all  the  accuracy  necessary  for  the  scale 
on  which  these  sections  and  diagrams  are  drawn. 

Another  factor  used  is  the  general  thickness  of  the  beds.  This  is  deter- 
mined by  measuring  them  where  they  outcrop  on  the  flanks  of  the  uplift. 


DESCRIPTION  OF  ILLUSTRATIONS.  175 

The  surface  lines,  the  outcrop  of  the  beds  along  these  lines,  and  the  thick- 
ness of  the  beds  are  factors  sufficient  for  the  construction  of  the  sections  and 
diagrams,  but  the  observed  dips  and  strikes  afford  many  valuable  checks  in 
their  construction. 

A  single  diagram  represents  displacement  and  degradation  in  two  dimen- 
sions; that  is,  in  a  vertical  plane  from  south  to  north  across  the  axis  of  up- 
heaval. A  group  of  these  diagrams  constructed  on  parallel  planes,  separated 
by  equal  intervals,  and  having  the  scale  of  these  intervals  in  the  group  the 
same  as  the  vertical  and  horizontal  scale  of  each  diagram,  serves  to  repre- 
sent displacement  and  degradation  in  three  dimensions. 

Stereogram. — To  more  fully  bring  the  displacement  into  visual  compre- 
hension, the  stereogram,  Plate  III,  has  been  constructed.  Here  the  lines 
representing  the  level  of  the  sea,  and  those  representing  the  present  surface 
are  omitted,  leaving  only  the  displacement  lines;  and  between  these  others 
have  been  interpolated,  so  that  the  intervals  are  but  3, 500  feet;  and  this  has 
the  effect  of  projecting  the  region  in  relief,  as  it  would  appear  in  a  bird's-eye 
view  had  there  been  displacement  but  no  degradation.  To  fully  compre- 
hend the  meaning  of  this  stereogram,  it  is  necessary  to  remember  that  every 
deviation  of  a  line  from  horizontality  represents  a  corresponding  inclination 
of  the  beds,  and  careful  inspection  will  show  that  absolute  horizontality  very 
rarely  occurs.  The  stereogram  fails  to  represent  the  abruptness  of  flexure 
in  some  places,  as  the  lines  of  displacement  show  the  intersection  of  vertical 
parallel  planes  with  the  summit  of  the  reproduced  bed,  and  these  planes  have 
a  north  and  south  direction.  Wherever  they  do  not  cross  a  flexure  in  the 
direction  of  the  dip,  but  to  a  greater  or  less  extent  oblique  to  it,  to  such 
extent  do  the  displacement  lines  fail  to  represent  the  abruptness  of  the  flexure 
or  angle  of  dip ;  in  other  words,  the  stereogram  does  not  fully  represent  dis- 
placement in  an  east  and  west  direction.  But  the  axis  of  flexure  in  the  Uinta 
Mountains  has  an  easterly  and  westerly  direction,  and  all  other  displace- 
ments are  subsidiary  to  this;  and  as  the  displacement  lines  are  drawn  trans- 
verse to  this  axis,  the  general  characteristics  are  well  represented.  It  fails 
also  to  give  the  relation  of  the  displacement  to  the  level  of  the  sea  except  in 
the  case  of  the  first  line  in  the  foreground. 

I  am  indebted  to  Mr.  Gilbert  for  this  method  of  illustration. 


176  STRUCTURAL  GEOLOGY. 

It  will  be  shown  hereafter  that  pari  passu  with  upheaval,  degradation 
progressed,  and  with  downthrow,  sedimentation,  and  it  .is  probable  that 
degradation  and  sedimentation  were  necessary  to  upheaval  and  downthrow. 
Yet,  for  certain  purposes,  it  is  desirable  that  displacement  be  considered  in- 
dependent of  the  degradation  with  which  in  nature  it  must  always  be  more 
or  less  complicated,  and  hence  the  stereogram  has  been  constructed. 

BircVs-Eye  View. — The  difference  between  upheaval  and  degradation  in 
the  region  of  uplift  can  be  determined  by  examining  the  diagrams  in  Plate  II; 
but  to  give  a  more  graphic  representation  of  this  important  fact  in  the  Uinta 
uplift,  the  bird's-eye  view,  Plate  IV,  has  been  constructed. 

Other  sections,  diagrams  and  stereograms  are  found  in  the  atlas,  to 
which  reference  will  be  made  in  appropriate  place.  All  of  these  sections, 
diagrams  and  stereograms  are  constructed  on  symmetrical  scales;  that  is, 
vertical  and  horizontal  scales  are  the  same  and  all  agree  with  the  map. 

THE  EASTERN  PORTION  OF  THE  UINTA  MOUNTAINS. 
DISPLACEMENT. 

The  Uinta  Mountains  have  been  produced  by  the  degradation  of  a  great 
upheaved  block  having  its  axis  in  an  east  and  wes't  direction.  This  axis  is 
not  a  straight  line ;  in  that  portion  of  the  range  under  discussion  it  makes  a 
great  curve  to  the  north;  on  the  western  border  of  the  district  the  axis  is 
found  at  Leidy's  Peak.  It  runs  a  little  north  of  Mount  Lena,  and  in  Brown's 
Park  it  passes  about  two  miles  north  of  Swallow  Canon,  then  it  deflects 

southward  and  is  found  ag-ain  on  Vermilion  Creek  about  four  miles  above 

%. 

its  mouth.  The  total  upheaval  above  the  sea  level,  along  its  axial  line,  is 
about  30,000  feet.  The  method  by  which  the  amount  of  uplift  is  ascer- 
tained is  as  follows:  It  is  in  evidence  that  the  upheaval  began  at  the  close 
of  the  Point  of  Rocks  period.  The  thickness  of  the  rocks  exposed  on  both 
flanks  of  the  uplift  below  that  horizon  is  a  little  more  than  25,000  feet,  and 
the  lowest  bed  seen  is  5,4.00  feet  above  the  level  of  the  sea.  The  Uinta 
Sandstone  has  not  been  lifted  as  high  at  Leidy's  Peak  as  it  has  at  the  mouth 
of  the  Vermilion  by  about  2,000  feet,  but  the  Mesozoic  groups  attenuate  from 
cast  to  west,  in  the  same  distance,  something  more  than  2,000  feet,  and 


DISPLACEMENT.  177 

hence  the  summit  of  the  Point  of  Rocks  Group  was  earned  about  as  high 
in  the  western  as  in  the  eastern  region. 

O 

From  the  axis  on  either  side  the  beds  are  flexed  in  a  gentle  curve  to 
the  north  and  south  for  many  miles  until  the  flanks  of  the  range  are  reached, 
where  the  beds  are  seen  to  drop  down  by  abrupt  flexures  or  faults,  and 
these  lines  of  maximum  displacement  are  subparallel  with  the  axis.  Thus 
a  great  block  having  its  longest  axis  in  an  easterly  and  westerly  direction 
was  uplifted.  In  some  places  this  block  was  severed  from  the  adjacent 
country  by  fracture;  in  some  places  by  more  or  less  abrupt  flexure;  and  it 
was  itself  flexed  gently  from  the  axis  either  way.  Nothing  more  is  needed 
to  explain  the  character  of  this  uplift  between  the  lines  of  maximum  dis- 
placement, but  the  latter  present  many  interesting  facts. 

On  Plate  III,  this  portion  of  the  Uinta  uplift,  together  with  the  dis- 
placements of  the  Yampa  district  are  represented  in  a  stereogram.  The 
general  axis  of  the  great  uplift  is  easily  recognizable,  as  is  also  the  gentle 
flexure  in  either  direction  from  this  axis.  Then  the  great  Uinta  fault  h,  h, 
h,  h  is  seen  on  the  north  with  the  Flaming  Gorge  branch  i,  i.  On  the  south 
side  of  the  Uinta  Mountains  in  the  Island  Park  district  we  find  the  north 
Ti-ra-kav  flexure  />*,  k,  k  and  the  south  Ti-ra-kav  flexure  /,  /,  L  In  the 
Yampa  district  on  its  northern  border  the  eastern  extension  of  the  north 
Ti-ra-kav  flexure  is  scarcely  seen,  as  there  is  an  oblique  area  of  upheaval 
between  the  Island  Park  sag  d,  d  and  the  Echo  Park  sag  e.  The  flexure  of 
the  Echo  Park  sag  also  becomes  less  abrupt  in  an  easterly  direction  until  it 
almost  fades  out.  The  displacements  south  of  the'Island  Park  and  Echo 
Park  sags  need  no  further  mention  here,  as  they  will  be  discussed  in  a  sub- 
sequent portion  of  this  chapter. 

It  will  be  seen  in  the  Island  Park  district  on  the  south  side  of  the 
Uinta  uplift  that  there  are  two  lines  of  maximum  downthrow  approxi- 
mately parallel,  the  north  and  south  Ti-ra-kav  flexures  ;  the  beds  between 
these  two  flexures  are  nowhere  horizontal.  The  south  Ti-ra-kav  flexure 
disappears  toward  the  west  until  the  region  embraced  in  the  stereogram  is 
passed  ;  a  little  farther  westward  it  re-appears,  sometimes  as  a  flexure  but 
usually  as  a  fault.  Passing  the  oblique  uplift  between  the  Island  Park  and 

*Echo  Park  sags  we  again  have  two  lines  of   maximum  downthrow.     The 
12  p  G 


178  STRUCTURAL  GEOLOGY. 

more  northern,  which  is  a  continuation  of  the  northern  Ti-ra-kav  flexure,  i# 
but  faintly  seen  in  the  stereogram ;  the  southern,  which  is  the  flexure  of  the 
Island  Park  sag,  is  more  pronounced.  All  of  these  maximum  flexures  on 
the  south  side  appear  to  be  but  slight  from  an  examination  of  the  stereo- 
gram,  as  its  scale  is  very  small  and  no  exaggeration  has  been  permitted ; 
but  they  are  very  important  characteristics  in  the  structural  geology  of  the 
region,  and  give  rise  to  very  remarkable  topographic  features.  In  the 
broad  generalization  necessitated  by  the  scale  of  the  illustration  many 
minute  displacements,  parallel,  oblique  and  transverse  to  these  larger,  dis- 
appear ;  that  is,  in  the  production  of  these  greater  flexures  the  beds  were 
locally  contorted  and  broken. 

Turning  now  to  the  north  side  of  the  Uinta  uplift,  we  find  that  the  line 
of  maximum  displacement,  beginning  at  the  eastern  extremity,  is  at  first  a 
gentle  flexure  with  comparatively  small  uplift;  but  the  flexure  rapidly 
increases  in  abruptness  and  magnitude  until  at  last  we  find  that  the  beds  are 
broken  and  we  have  a  fault ;  but  only  a  portion  of  the  uplift  is  by  faulting, 
and  the  beds  on  the  thrown  side  are  turned  up  at  the  edge.  Farther  west- 
ward the  beds  below  lie  nearly  horizontal,  and  the  beds  on  the  upheaved 
side  are  flexed  downward;  and  these  conditions  alternate  so  that  we  some- 
times have  the  upheaved  beds  flexed  downward  only,  while  the  thrown  beds 
are  nearly  or  quite  horizontal.  Again,  we  have  the  upheaved  beds  nearly 
horizontal  at  the  edge  and  the  thrown  beds  decidedly  flexed  upward;  and 
another  variation  is  found  where  the  upheaved  beds  are  flexed  downward 
and  the  thrown  beds  upward. 

It  is  probable  that  the  displacement  began  by  flexure,  and  continued 
until  much  of  it  was  made  in  this  way,  and  finally  the  beds  broke,  and  the 
latter  part  of  the  displacement  was  by  faulting.  And  when  this  faulting 
occurred,  in  some  places  the  beds  broke  on  the  side  of  the  flexure  nearer  the 
axis,  in  other  places  on  the  side  of  the  flexure  farther  from  the  axis,  and  in 
still  other  places  between  the  sides  of  the  flexure ;  that  is,  the  line  of  fracture 
meanders  along  the  zone  of  flexure.  As  we  approach  the  Flaming  Gorge 
district  we  find  that  the  faulting  is  greatly  diminished,  while  the  flexing  is 
increased,  the  total  throw  or  uplift,  as  we  may  please  to  consider  it,  remaining 
approximately  the  same.  At  last  this  line  of  abrupt  displacement  branches, 


DISPLACEMENT.  179 

and  we  have  a  faulted  flexure  to  the  south  and  an  abrupt  flexure  to  the 
north;  the  southern  branch,  farther  westward,  becomes  a  simple  flexure, 
and  the  northern  branch  changes  its  course  somewhat,  so  that  the  beds  are 
greatly  warped;  then  it  becomes  a  faulted  flexure,  and  finally  a  clean  fault. 

Thus  the  great  Uinta  block  was  uplifted,  behaving  in  part  as  an  integer 
to  the  extent  that  it  was  separated  by  flexure  and  fracture  from  the  adjacent 
country,  and  as  a  body  of  minute  parts  as  it  was  flexed  along  the  axial  line. 

We  are  interested  to  know  at  what  rate  this  great  uplift  progressed. 
The  evidence  bearing  on  this  point  is  of  three  classes:  first,  that  derived 
from  the  character  of  the  displacement  itself;  second,  that  derived  from 
degradation;  and  third,  that  derived  from  sedimentation. 

The  displacement  is  partly  by  faulting,  partly  by  flexing.  A  priori,  it 
would  appear  that  whether  any  given  displacement  should  be  by  faulting 
or  flexing  would  be  determined  by  four  conditions,  severally  or  conjointly: 
first,  rate  of  displacement;  second,  constitution  of  the  beds  displaced,  flexi- 
ble and  brittle  beds  being  contrasted;  third,  the  depth  of  the  beds  consid- 
ered, for  the  deeply  seated  beds,  being  less  free  to  move,  would  be  more 
liable  to  bend,  and  beds  nearer  the  surface,  being  more  free  to  move,  more 
liable  to  break;  and  fourth,  the  nature  or  application  of  the  force  producing 
displacement.  Observed  facts  show  that  two  at  least  of  these  a  priori  condi- 
tions, the  second  and  third,  are  true  conditions.  Both  Mr.  Gilbert  and  myself 
have  observed  in  the  transverse  section  of  a  displacement  that  the  hard  beds 
have  been  broken  and  the  soft  beds  bent,  and  I  have  elsewhere  published 
such  a  section. 

In  a  region  of  country  visited  by  Mr.  Gilbert  during  the  past  season, 
he  found  that  the  displacement  in  one  district  was  by  faulting,  and  in  an- 
other by  flexing.  In  the  region  of  faulting  there  had  been  but  little  sub- 
sequent degradation ;  in  the  region  of  flexing,  much  subsequent  degrada- 
tion; and  these  conditions  led  Mr.  Gilbert  to  the  conclusion  that  the 
depth  of  the  beds  below  the  general  surface  at  the  time  of  the  displacement 
had  determined  these  characteristics,  and  in  studying  facts  which  had  been 
collected  in  other  regions  by  myself,  he  was  able  to  show  that  they  also 
lead  to  the  same  conclusions.  The  places  where  these  facts  were  observed 
are  so  widely  spread  throughout  the  Plateau  Province  that  it  will  not '  be 


180  STRUCTURAL  GEOLOGY. 

convenient  to  assemble  them   here,  but  I  am  strongly  disposed  to  accept 
Mr.  Gilbert's  conclusions. 

The  fourth  condition  is  supposable,  but  that  it  is  a  vera  causa  I  cannot 
nay.  I  have  often  supposed  it  to  be  such  in  the  study  of  particular  faults, 
but  on  further  study  it  has  eluded  my  apprehension.  We  sometimes 
iind  a  displacement  of  many  thousand  feet  where  the  uplifted  region  is 
separated  from  the  thrown  by  a  broad  zone  of  gently  dipping  beds, 
and  it  would  seem  a  priori  that  where  two  regions  were  thus  separated, 
the.  zone  of  change  would  be  by  flexure  rather  than  by  a  series'  of 
ruptures,  and  such  is  usually  though  not  invariably  the  case,  and  this  seems 
to  be  a  question  of  application  of  force,  or  in  other  words,  character  of 
strain,  and  it  cannot  be  doubted  that  such  a  condition  must  be  taken  into 
consideration.  Mr.  Gilbert- evidently  recognizes  it  as  a  true  cause,  for  in 
discussing  the  Basin  Ranges,Jie  says:  "  The  displacement  of  comparatively 
rigid  bodies  of  strata  by  vertical  or  nearly  vertical  faults,  involves  little  hor- 
izontal diminution,  and  suggests  the  application  of  vertical  pressure  from 
below." 

As  to  the  first  cause,  rate  of  displacement,  it  is  manifest  that  accelera- 
tion promotes  rupture,  retardation,  flexure;  but  the  other  conditions  which 
I  have  set  forth  so  modify  this  rule,  that  rate  of  displacement  cannot  with 
any  certainty  be  determined  from  facts  of  flexure  and  rupture  alone. 

The  Uinta  upheaval  was  partly  by  flexing,  partly  by  faulting,  and  if 
there  were  no  other  conditions  to  determine  these  characteristics,  we  might 
say  that  so  far  as  the  beds  were  flexed  they  give  evidence  of  slow  move- 
ment; and  so  far  as  they  were  ruptured,  evidence  of  a  more  rapid  move- 
ment; and  the  twenty -five  or  thirty -thousand  feet  of  beds  which  cfcre 
exposed  to  view  and  were  involved  in  this  uplift  were  chiefly  of  a  character 
quite  brittle,  and  this  increases  the  evidence  in  favor  of  #low  upheaval  by 
flexing ;  but  flexing  may  have  been  at  great  depths,  and  the  superincumbent 
masses  produced  a  condition  favorable  to  flexing  even  in  a  rapid  rate  of 
movement.  Many  substances,  especially  metallic,  are  known  to  flow  under 
great  pressure,  and  it  is  probable  that  great  pressure  would  produce  in  all 
rocks  a  quasi-fluid  condition,  and  hence  we  cannot  say  that  flexing  attests 
to  a  slow  rate.  On  the  other  hand,  faulting,  without  considering  other  con- 


DEGRADATION. 

* 

ditions,  would  seem  to  attest  to  rapid  rate,  but  the  character  of  the  strain 
may  have  determined  the  rupture.  Hence  we  may  conclude  that  the 
characteristics  of  the  displacement  do  not  afford  satisfactory  evidence  of  the 
rate  of  its  movement. 

It  will  be  seen  hereafter  that  facts  relating  to  degradation  and  sedimen- 
tation do  give  some  satisfactory  conclusions. 

DEGRADATION. 
EXTENT   OF   DEGRADATION. 

The  area  of  degradation  which  I  have  often  for  convenience  called  the 
region  of  uplift,  represented  in  Plate  II,  embraces  a  little  more  than  2,800 
square  miles.  From  this  about  8,300  cubic  miles  of  rock  have  been  carried 
away  by  rains  and  rivers — a  mean  degradation  of  about  three  cubic  miles 
to  the  square  mile  But  a  part  of  the  region  embraced  on  that  plate  will 
be  discussed  hereafter  under  the  head  of  Yampa  Plateau,  and  in  what  I 
have  said  concerning  the  Uinta  Mountains  above,  this  region  has  not  been 
considered.  Taking  the  Uinta  Mountain  region  proper,  then,  we  have  an  area 
of  about  2,000  square  miles  from  which  about  7,100  cubic  miles  of  rock  have 
been  taken,  giving  a  mean  degradation  of  3^  cubic  miles  to  every  square  mile 
of  surface.  But  this  has  not  been  taken  from  all  points  equally ;  a  greater 
amount  has  been  carried  from  the  axial  region  than  from  the  districts  along 
the  flanks ;  and  in  the  axial  region  a  greater  amount  has  been  taken  from 
the  eastern  than  from  the  western  end.  Here  where  the  displacement  lines 
are  carried  highest,  the  surface  lines  are  lowest,  so  that  the  degradation  is 
more,  not  only  by  the  amount  of  greater  uplift  but  also  by  an  additional 
amount  in  the  deeper  excavation  of  the  valley.  The 'region  of  highest 
uplift  is  the  region  of  lowest  degradation,  and  here  more  than  25,000  feet 
of  beds  have  been  removed. 

To  more  fully  comprehend  the  amount  of  degradation  and  its  relation  to 
upheaval,  the  bird's-eye  view,  Plate  IV,  has  been  constructed.  Here  we 
have  represented  a  block  from  the  Uinta  Mountains  forty  miles  in  a  north 
and  south,  and  fifty  miles  in  an  east  and  west,  direction.  The  one-half  of 
the  view  in  the  foreground  represents  the  degraded  region,  and  the  one -half 


182  STUCTURAL  GEOLOGY. 

in  the  background  as  it  would  appear  had  there  been  no  degradation,  but 
uplift  only.  It  is  believed  that  a  careful  study  of  the  illustration  will  be 
amply  repaid. 

RATE  OF   DEGRADATION. 

It  would  be  interesting  to  know  at  what  rate  this  degradation  has  pro- 
gressed. We  know  of  no  means  by  which  an  absolute  rate  can  be  deter- 
mined, but  there  are  certain  facts  which  lead  to  the  conclusion  that  a 
maximum  rate  for  this  region  was  never  established.  These  facts  are 
found  in  the  character  of  the  topographic  features  produced  by  degradation, 
but  in  order  that  we  may  more  fully  understand  them  it  will  be  well  to 
.briefly  examine  the  agencies,  methods,  and  conditions  of  degradation. 

Degradation  consists  of  disintegration  and  transportation,  and  they  are 
mutually  dependent  parts  of  the  general  process.  If  disintegration  is  re- 
tarded, transportation  is  retarded,  for  the  materials  must  be  furnished  ready 
for  transportation.  Again,  if  transportation  is  retarded,  disintegration  is  re- 
tarded, as  the  beds  to  be  disintegrated  are  to  some  extent  protected  by  the 
accumulated  products  of  the  process ;  and  if  either  is  accelerated,  the  other 
must  be  accelerated. 

DISINTEGRATION. 

The  rock  masses  which  are  brought  above  the  level  of  the  sea  by  up- 
heaval are  always  found  to  be  more  or  less  coherent.  Although  these  rocks 
are  chiefly  of  sedimentary  origin,  the  exceptions  being  extravasated  masses, 
still  they  are  usually  found  to  have  assumed  a  more  or  less  crystalline  struc- 
ture, due  either  to  •  the  manner  of  their  deposition  or  subsequent  metamor- 
phism,  so  that  the  minute  parts,  molecular  or  mechanical,  of  which  these  rocks 
were  originally  aggregated,  cohere  in  great  masses.  There  are  many  degrees 
of  this  coherence  from  bad-land  sandstones  or  shales  of  extreme  friability  to 
schists  and  granites  of  extreme  coherence;  but  whatever  may  be  their  degree 
of  coherence,  they  must  be  disintegrated  prior  to  their  transportation  to 

the  sea. 

PETROLOGY  AS  RELATED  TO  DISINTEGRATION. 

The  endurance  of  rocks  as  determined  by  their  coherence  depends  on— 
1.   Geologic  Structure. — The  rocks  may  be  irregularly  massed  or  strati- 


DEGRADATION.  183 

fied ;  the  latter  yield  more  readily  than  the  former.  The  strata  may  be  thick 
or  thin;  the  latter  yield  more  readily  than  the  former.  The  strata  may  be 
horizontal  or  inclined,  and  the  latter  yield  more  readily  than  the  former; 
and  in  each  condition  above  mentioned  heterogeneity  promotes  disinte- 
gration. 

2.  Litholoffic  Structure. — Under  this  head  we  may  consider  whether  the 
beds  are  compacted  crystals  or  cemented  sediments;  the  latter  yield  more 
readily  than  the  former,  and  heterogeneity  promotes  disintegration.     Both 
in  detrital  and  crystalline  rocks  there  are  certain  conditions  which  may  be 
grouped  under  the  head  of  induration,  including  hardness  and  toughness,  and 
the  greater  the  induration  the  greater  the  stability;  and  the  law  of  hetero- 
geneity applies  also  to  this  condition. 

3.  Chemical  Structure. — The  principal  condition  of  chemical  constitu- 
tion relating  to  endurance  is  solubility;  the  soluble  yield  more  readily  than 
the  insoluble,  and  in  chemical  constitution  the  homogeneous  is  more  stable 
than  the  heterogeneous. 

It  will  thus  be  seen  that  in  each  particular  mentioned  above,  the  homo- 
geneous is  more  stable  than  the  heterogeneous,  and  these  particulars  in  their 
correlations  are  themselves  conditions  of  heterogeneity,  so  that  the  whole 
subject  of  petrology  in  its  relation  to  disintegration,  is  one  of  degree  of 

heterogeneity. 

DYNAMICS   OF   DISINTEGRATION. 

The  principal  forces  of  disintegration  are  gravity,  heat,  crystallization 
and  chemical  reaction.  Gravity  disintegrates  the  rocks  directly  where  they 
break  from  cliffs  and  ledges  partly  by  their  own  weight,  and  are  further  dis- 
integrated by  the  fall,  and  indirectly  through  the  agency  of  water  in  abra- 
sion. Heat  disintegrates  the  rocks  by  change  of  temperature,  and  probably 
by  expansion  of  water  permeating  the  rocks.  Crystallogenic  force  also  acts 
through  the  agency  of  water,  for  where  the  water  which  has  permeated  the 
rocks  is  frozen,  the  expansion  due  to  this  crystallization  breaks  them  asun- 
der. In  chemical  reaction  the  rocks  are  broken  up  through  the  agency  of 
water  which  acts  directly  in  dissolving  them,  or  indirectly  in  promoting 
other  chemical  reactions. 


JS4  STRUCTURAL   GEOLOGY. 

In  disintegration,  therefore,  we  have  an  intricate  plexus  of  forces  acting 
on  an  intricate  plexus  of  matter. 

Now,  so  far  as  disintegration  depends  on  the  forces  of  heat,  crystalli- 
zation, and  chemical  change,  the  climate  of  the  region  is  involved,  aridity 
being  contrasted  wi,th  humidity,  heat  with  cold,  and  great  changes  in  either 
factor  of  climate  promote  disintegration ;  and  so  far  as  disintegration  de- 
pends on  gravity,  the  declivity  of  the  surface  exposed  to  degradation  is  in- 
volved, and  a  breaking  up  of  the  general  declivity  into  greater  and  lesser 
slopes,  promotes  disintegration.  We  may,  therefore,  discuss  the  dynamics  of 
disintegration  as  conditions  of  climate  and  declivity,  and  hence  we  may 
consider  the  factors  of  disintegration  to  be  petrology,  climate  and  declivity, 
and  affirm  that  if  the  rate  of  transportation  is  sufficient  to  allow  the  forces 
of  disintegration  to  act  to  their  fullest  extent,  the  rate  of  disintegration  will 
depend  on  the  heterogeneity  of  the  rocks,  heterogeneity  of  climate,  and 
heterogeneity  of  declivity. 

TRANSPORTATION. 

Gravity  is  the  force  acting  in  transportation.  It  acts  directly  in  trans- 
porting masses  which  fall  from  ledges  and  cliffs,  and  indirectly  through  the 
agency  of  water.  In  this  indirect  method  there  are  two  sources  for  the 
mechanical  motion  involved  in  the  process:  the  one  is  the  force  of  gravity 
inhering  in  the  water,  which  is  the  vehicle  of  transportation,  the  other  the" 
force  of  gravity  inhering  in  the  rocks  transported.  Let  us  call  the  latter 
rock  power,  the  former  water  power,  and  the  rock  material  transported,  load. 

It  is  manifest  that  if  the  rocks  on  disintegration  were  in  a  fluid  state, 
their  owrrgravity  would  transport  them.  All  of  the  rock  material  which  is 
dissolved  is  placed  in  this  condition,  and  its  own  gravity  is  the  force  which 
transports  it;  it  does  not  float  on  the  water,  but  behaves  as  an  integral  part 
of  it,  and  with  it  obeys  the  laws  of  hydrodynamics.  In  this  case  the  water 
is  not  the  agent  of  transportation,  but  only  the  agent  of  disintegration. 

When  the  rocks  are  disintegrated  mechanically  the  water  is  properly 
the  vehicle  of  transportation,  and  we  have  two  cases,  the  one  in  which  the 
load  is  driven  by  the  water,  the  other  in  which  it  is  floated  on  the  water. 
When  the  transported  matter  is  driven  by  the  water  along  the  bottom  of  the 


DEGRADATION.  185 

channel,  both  rock  power  and  water  power  are  employed,  these  two  forces 
acting  in  inverse  ratio  with  the  specific  gravity  of  water  and  load;  that  is, 
less  water  power  is  needed  to  drive  the  rock  by  the  amount  of  the  weight 
of  the  water  displaced  by  the  rock,  for  to  this  extent,  rock  power  is  used. 

The  amount  of  load  which  may  be  transported  by  the  driving  process, 
or  in  other  words,  by  water  power,  plus  an  amount  of  rock  power,  begins 
with  that  degree  of  comminution  which  permits  the  load  to  be  moved,  and 
is  limited  by  the  power  of  the  water  on  one  hand  and  by  friction  on  the 
other.  And  wherever  the  degree  of  comminution  is  such  that  the  matter 
is  transported  partly  or  wholly  by  the  agency  of  flotation  to  such 
extent  as  flotation  is  employed,  the  driving  ceases  and  other  limits  are 
imposed. 

We  come  now  to  the  principal  method  of  transportation ;  that  is,  that 
by  flotation.  Here  the  rock  power  is  used  in  transportation,  and  the 
water  is  the  vehicle.  If  the  matter  to  be  floated  is  of  the  same  or  less 
specific  gravity  than  the  water,  a  condition  seldom  obtaining,  flotation  is 
perfect,  and  the  water  power  is  not  used  either  in  transportation  or  to  pro- 
mote flotation.  But  when  the  floating  matter  is  of  greater  specific  gravity 
than  the  water,  then  the  water  power  is  used  in  promoting  flotation.  With 
a  given  amount  of  water  and  sufficient  supply  of  load,  the  extent  to  which 
the  water  power  will  be  utilized  in  promoting  flotation  will  depend  on  two 
conditions  :  First,  the  power  of  the  water,  which  is  measured  by  fall  into 
mass,  or  which  may  be  expressed  as  velocity  or  again  as  declivity ;  second, 
it  will  depend  on  the  relation  which  exists  between  the  floating  surface,  or 
surface  presented  downward,  and  the  mass  of  each  particle  of  the  load. 
In  other  words,  it  will  depend  on  the  specific  gravity  and  comminution 
of  the  load.  If  the  specific  gravity  of  the  load  is  but  little  greater  than 
water,  the  velocity  of  the  water  becomes  a  very  small  factor,  and  the 
amount  which  can  be  transported  will  be  chiefly  limited  by  the  containing 
capacity  of  the  water,  but  this  is  a  condition  not  actually  found  in  nature. 
The  difference  between  the  specific  gravity  of  water  and  load  is  great,  and 
variable  within  such  small  limits  that  the  variability  may  be  neglected ;  but 
the  relation  between  the  floating  surface  and  the  mass  of  each  particle  of 
load  may  be  determined  by  another  condition  than  that  of  specific  gravity, 


186  STRUCTURAL    GEOLOGY. 

i.  e.,  size;  for  the  ratio  between  the  floating  mass  of  a  body,  or  the  surface 
presented  downward,  and  the  mass  of  the  body,  increases  with  the  diminu- 
tion of  a  body.  Then  if  the  body  is  smaller,  the  ratio  between  the  floating 
surface  and  mass  is  larger;  and  hence  comminution  promotes  flotation.  If 
this  comminution  is  great,  approaching  complete  or  molecular  comminution, 
the  velocity  of  the  water  again  becomes  a  small  factor,  and  the  amount  of 
transportation  chiefly  depends  on  the  containing  capacity  of  the  water ;  but 
as  comminution  is  less  and  the  size  of  the  particles  larger,  some  force  must 
intervene  to  promote  flotation,  and  this  is  derived  from  the  water  power ; 
and  to  sustain  the  same  amount  of  flotation  more  of  this  force  must  be 
utilized  as  the  size  of  the  particles  increase.  The  amount  of  this  force  from 
which  must  be  drawn  the  supply  in  supporting  flotation  depends,  cceterispar- 
ibus,  on  the  velocity  or  declivity,  but  practically  the  whole  force  is  rarely 
utilized. 

The  extent  to  which  this  force  is  utilized  depends  upon  many  complex 
conditions  by  which  the  motion  in  the  flowing  water  may  be  transmitted  to 
the  load.  To  float,  the  particles  of  rock  must  be  suspended  in  the  water,  and 
as  they  fall  from  suspension  during  the  process  of  transportation,  they  must 
be  resuspended,  so  that  the  water  power  must  be  used  in  lifting,  and  this  is 
done  by  the  creation  of  secondary  currents  in  regurgitation,  eddying,  boil- 
ing, &c.,  or  movements  in  the  water  transverse  or  oblique  to  the  direction  of 
the  flow,  all  of  which  impede  the  flow.  If  the  flow  is  perfect  no  lifting  can 
be  done ;  so  these  secondary  currents  are  produced  by  locally  diverting  the 
flow  from  its  normal  course,  and  this  diversion  to  secure  lifting  must  be  di- 
rectly or  indirectly  upward  ;  the  greater  and  oftener  this  diversion  the  more 
lifting  will  be  done.  In  other  words,  we  may  say  that  water  power  is  ap- 
plied to  the  lifting  of  the  particles  and  thus  promotes  flotation  by  hetero- 
geneity of  flow,  and  this  heterogeneity  of  flow  is  induced  by  the  heterogeneity 
of  channel  in  both  horizontal  and  vertical  direction,  but  chiefly  in  the  lat- 
ter. And  in  obedience  to  well  known  laws  of  friction  this  heterogeneity  of 
flow  is  greatly  increased  by  intensifying  the  flow,  or  in  other  words,  increas- 
ing the  velocity  of  the  water ;  and  velocity  is  due  to  declivity.  And  that 
heterogeneity  of  channel,  which  by  producing  heterogeneity  of  flow  utilizes 
the  water  power  in  lifting  the  load,  is  also  due  to  declivity  ;  and  hence  it 


DEGRADATION.  187 

remains,  first,  that  the  water  power,  cceteris  paribus,  is  a  function  of  declivity ; 
and,  second,  the"  utilization  of  the  water  power,  cceteris  paribus,  is  a  function 
of  declivity ;  so  that  with  a  given  amount  of  water  and  sufficient  supply  of 
load,  the  rate  of  transportation  through  the  agency  of  flotation  depends  on 
declivity  ;  and  the  amount  of  transportation  through  driving  also  depends 
on  declivity.  Therefore  the  rate  of  transportation  of  all  mechanically  com- 
minuted matter  is  determined  by  declivity. 

I  have  spoken  of  the  containing  capacity  of  water  for  load  of  the  same 
or  less  specific  gravity  than  water,  but  the  amount  of  such  load  is  so  minute 
in  comparison  with  the  whole  amount  that  we  may  neglect  it.  Again,  I 
have  spoken  of  the  containing  capacity  of  water  for  particles  of  load  of 
greater  specific  gravity  than  water;  the  amount  of  matter  transported  in 
this  way  is  great,  but  usually  the  supply  is  so  limited  that  the  containing 
capacity  is  rarely  reached ;  but  it  seems  probable  from  observations  made 
on  transportation  of  bad-land  detritus  that  there  are  times  when  this  con- 
taining capacity  is  actually  reached,  when  the  amount  transported  is  limited 
by  this  condition,  that  is,  containing  capacity.  Then  what  is  this  contain- 
ing capacity  ?  In  matter  of  this  character  without  water  the  rock  power 
cannot  overcome  interstitial  friction,  and  hence  the  matter  is  not  transported. 
In  order  that  it  may  be  transported  by  rock  power  it  is  necessary,  first,  that 
the  interstitial  spaces  shall  be  filled  with  water;  and,  second,  that  an  amount 
of  water  be  added  sufficient  to  reduce  interstitial  friction  so  that  it  may  be 
overcome  by  rock  power.  And  it  is  possible  that  this  can  be  determined 
mathematically  for  particles  of  any  given  form,  size  and  weight ;  but  in 
nature  these  forms  are  multifarious,  and  the  determination  of  the  containing 
capacity  is  a  proper  subject  of  experiment.  I  know  of  no  such  experiments 
having  been  made ;  but,  from  observations  in  nature,  I  am  led  to  the  con- 
clusion that  the  containing  capacity  of  water  for  particles  of  this  nature  is 
at  least  three  times  its  own  weight. 

Again  I  must  remark  that  the  last  mentioned  condition  of  transportation 
is  of  very  infrequent  occurrence;  and  it  remains,  then,  that  in  general  trans- 
portation, the  rate  is  determined  by  declivity. 

Having  now  examined  the  processes  of  disintegration  and  transporta- 
tion separately,  we  will  examine  them  as  combined  in  the 


188  STRUCTURAL    GEOLOGY. 

METHODS  OF  DEGRADATION. 

These  are,  first,  erosion  or  degradation  of  the  general  surface;  second, 
corrasiori  or  degradation  of  the  stream  channels ;  and,  third,  sapping  or  deg- 
radation of  cliffs. 

EROSION. — This  is  distributed  over  the  general  surface;  the  rocks  are 
disintegrated  by  climatic  agencies  and  transported  into  streams  by  the  wash 
of  rains,  both  by  driving  and  flotation,  and  flotation  is  largely  promoted  by 
the  beating  of  rains.  In  this  method  the  rate  of  degradation  depends  on  the 
rate  of  transportation.  This  is  a  fact  of  almost  universal  observation;  for 
wherever  there  is  soil  or  loose  earth,  the  amount  of  such  matter  is  the  excess 
of  disintegration  over  transportation. 

We  have  already  seen  in  the  former  analysis  of  transportation  that 
with  a  given  quantity  of  water,  transportation  will  depend  on  declivity,  but 
in  the  transportation  belonging  to  this  method  of  degradation  the  quantity 
of  water  is  a  factor  of  transportation  only  to  a  limited  extent,  for  increased 
rainfall  promotes  the  growth  of  vegetation  which  serves  as  a  protection  to 
the  soil.  Nor  is  this  protection  inconsiderable,  for  it  preserves  the  rocks 
from  the  beating  of  the  storms,  and  prevents  the  waters  from  gathering  rap- 
idly into  rills  and  brooks,  and  strains  the  water  of  its  earthy  sediments.  I 
have  many  times  witnessed  the  action  of  a  -  storm  in  an  arid  region  where 
the  disintegrated  rocks  were  unprotected  by  forests,  shrubbery,  or  turf,  and 
as  often  have  I  been  impressed  with  the  wonderful  power  of  the  infrequent 
storm  to  gather  up  and  carry  away  the  land,  as  compared  with  the  frequent 
storm  in  the  prairie  or  forest  of  a  land  more  richly  clad.  The  same  contrast 
may  be  observed  in  a  region  brought  under  the  dominion  of  man  by  culti- 
vation where  the  surface  of  a  plowed  field  is  swept  away  by  a  storm,  and 
the  furrows  are  the  channels  for  floods  of  mud,  while  the  meadow  receives 
the  rain  with  outstretched  arms  of  verdure,  which  bear  it  gently  to  the  earth, 
where  it  is  gathered  into  quiet  rills,  which  feed  a  stream  made  turbid  it  is 
true,  but  pure  when  compared  witli  the  stream  of  mud  flowing  from  the  field 
from  which  the  plowman  was  driven  by  the  storm. 

Erosion,  then,  or  surface  degradation  is  not  greatly  promoted  by 
increased  rainfall,  and  it  may  be  that  its  effect  is  rather  to  retard  the  pro- 


DEGRADATION.  189 

cess;  but  the  difference  between  greater  or  lesser  rainfall  is  plainly  manifest 
in  the  topographic  features  produced — little  rainfall  giving  angular  reliefs ; 
much,  rounded  reliefs. 

Neglecting  such  a  hypothetic  condition  as  no  rainfall,  we  have  in  nature 
to  consider  only  greater  or  lesser  raiiffall.  With  greater  rainfall  we  have  a 
greater  power,  but  a  lesser  utilization  of  the  power;  with  lesser  rainfall  we 
have  lesser  power,  but  greater  utilization;  and  in  these  varying  conditions, 
just  where  maximum  degradation  is  found  I  am  not  able  to  state.  Hence, 
in  the  process  of  degradation  which.  I  have  called  erosion,  we  have  simply 
to  consider  declivity,  with  exceptions  so  minute  that  they  may  be  neglected. 

Now,  it  must  be  taken  into  consideration  that  this  is  the  most  import- 
ant method  of  degradation,  as  it  acts  everywhere  on  the  dry  land;  but, 
because  its  operations  are  so  greatly  diffused,  being  universal  in  its  action 
on  dry  land,  it  is  so  subtle  and  minute  in  its  manifestations  within  any  area 
which  may  come  immediately  under  the  eye  that  its  efficiency  is  apt  to  be 
underrated. 

CORRASION. — This  is  the  action  of  waters  gathered  into  streams  where 
their  operations  are  confined  to  more  limited  areas,  that  is,  along  the  chan- 
nels of  such  streams.  Here  the  material  supplied  from  the  surrounding 
surfaces  by  erosion  is  further  transported  by  the  streams,  and  in  the  process 
of  transportation  becomes  the  instrument  used  in  disintegrating  the  stream 
beds;  and  the  material  thus  disintegrated  is  added  to  that  furnished  by  ero- 
sion, and  with  it  is  transported  by  the  streams,  and  this  added  material  also 
becomes  an  instrument  of  disintegration. 

The  force  used  in  disintegration  is  rock  power  and  water  power;  load 
is  the  instrument,  water  the  agent.  All  processes  of  solution  are  neglected. 

The  force  of  rock  power  and  water  power  is  measured  by  mass  into 
fall,  and  this  may  be  considered  as  declivity;  the  specific  gravity  of  the 
instrument  not  being  greatly  variable  may  be  neglected.  There  are  other 
conditions  of  instrument,  such  as  hardness  and  angularity  of  particles,  which 
for  any  given  particle  might  be  of  value  in  determining  its  efficiency;  but, 
in  the  multifarious  particles  of  diverse  hardness  and  form,  a  general  average 
will  be  established  for  streams,  variable  within  such  small  limits  that  these 
conditions  also  may  be  neglected.  The  only  condition  of  instrument  of 


190  STRUCTURAL   GEOLOGY. 

sufficient  importance  to  be  considered  in  this  connection  is  size  of  particles, 
for  the  utilization  of  the  particles  as  instruments  is  dependent,  cceteris  paribus, 
on  their  size.  If  the  particles  be  too  large  they  cannot  be  transported,  arid 
thus  cannot  be  used  as  instruments;  and  within  the  limits  of  size  transported, 
a  greater  amount  of  instrument  will  fae  used  as  the  size  of  the  particles 
diminish;  that  is,  witli  a  given  stream,  the  instrument  is  increased  with  com- 
minution of  instrument,  the  instrument  being  the  load,  and  load  being 
increased  by  comminution  as  has  been  seen. 

We  have  next  to  consider  the  beds  to  be  corraded,  and  so  far  as  their 
constitution  is  a  factor  in  corrasion,  it  may  be  brought  into  the  simple 
expression  that  heterogeneity  promotes  corrasion.  But  a  part  of  the  instru- 
ment of  corrasion  is  derived  from  the  rocks  corraded;  and  as  heterogeneity 
of  these  rocks  promotes  disintegration,  and  to  the  same  extent  promotes  corra- 
sion, it  further  augments  the  instrument  of  corrasion  in  the  channel  below. 
But  it  has  been  seen  that  in  transportation  the  utilization  of  the  water  power 
in  promoting  flotation  as  a  function  of  heterogeneity  of  flow  is  a  function  of 
declivity  cceteris  paribus.  Hence,  declivity  not  only  increases  the  force,  but 
it  also  utilizes  the  force,  and,  hence,  multiplies  itself  as  a  factor  of  corrasion. 
A  part  of  the  instrument  in  corrasion  is  the  load  of  the  stream  derived  from 
erosion;  and  we  have  already  seen  that  the  amount  of  this  load  depends 
chiefly  upon  declivity «$  hence,  the  amount  of  instrument  from  this  source 
depends  on  declivity  of  erosion,  and  the  amount  of  instrument  derived  from 
corrasion  depends  on  declivity;  and  the  power  of  corrasion,  that  is,  rock 
power  plus  water  power,  depends  on  declivity.  Hence,  with  a  given  quan- 
tity of  water  and  a  given  character  of  bed,  rate  of  corrasion  depends  on 
declivity.  Again,  rapid  corrasion  increases  the  declivity  of  erosion,^:  and 
hence  increases  erosion;  and  this  increased  erosion  augments  the  instru- 
ment of  corrasion,  hence,  increases  corrasion;  and  declivity  by  the  two 
methods  of  degradation  enters  the  general  problem  of  degradation  as  a  factor 
with  a  rapidly  increasing  value. 

Corrasion  is  a  very  important  method  of  degradation,  although  its  results 
are  of  much  less  magnitude  than  those  of  erosion.  The  evidence  of  this  can 
be  seen,  and  the  results  often  strike  the  student  of  physical  geography  with 
great  force.  The  deep  channels  in  which  the  rivers  run  are  grand  topo- 


DEGEADATION.  191 

graphic  features.  Deep  river  valleys  and  mountain  gorges  are  everywhere 
seen  to  have  been  produced  by  this  agency,  and  the  power  of  the  streams  in 
carving  their  winding  paths  is  readily  comprehended.  But  the  magnitude 
of  this  agency  is  more  thoroughly  brought  into  visual  comprehension  in  the 
caiions  that  traverse  the  Plateau  Province,  for  here  erosion  has  not  kept  pace 
with  corrasion.  All  the  processes  of  erosion  and  sapping  serve  to  obliterate 
the  evidences  of  corrasion,  and  the  latter  appears  more  plainly  as  its  pro- 
gress exceeds  that  of  the  other  methods;  but  still  the  evidences  of  corrasion 
rarely  disappear  until  the  land  is  buried  by  the  sea;  for  wherever  an  area  of 
land  is  above  its  base  level  of  degradation,  there  corrasion  will  be  manifest 
by  deepening  its  channel;  and  wherever  the  dry  land  has  been  brought 
down  near  to  its  base  level,  there  corrasion  is  manifest  by  widening  its 
channel. 

There  is  another  method  of  degradation  to  be  considered,  viz : 
SAPPING. — The  walls  that  inclose  the  channels  of  corrasion  are  broken 
down  by  gravity,  and  when  in  the  progress  of  corrasion  the  channel  of  a 
stream  reaches  beds  which  easily  disintegrate,  having  passed  through  beds 
which  disintegrate  but  slowly,  degradation  is  increased  by  an  undermining 
process,  and  as  corrasion  still  continues  through  a  series  of  yielding  and 
unyielding  beds,  the  walls  of  the  streams  are  carried  back  in  a  series  of  steps, 
the  tread  of  each  step  being  the  summit  of  a  harder  bed,  the  rise  of  each  step 
the  escarped  edge  of  the  harder  bed  above,  underlaid  by  the  softer.  It  is 
manifest  that  the  conditions  favorable  to  the  continuatiorh  of  this  cliff  degra- 
dation to  any  great  distance  back  from  the  stream  are  found  only  where  the 
beds  are  horizontally,  or  nearly  horizontally  stratified.  But  sapping  is  not 
confined  to  the  undermining  of  walls  produced  by  corrasion,  but  is  carried 
on  in  simple  anticlinal  upheavals  from  the  axis  toward  the  flanks;  in  up- 
heavals of  the  Uinta  type,  in  like  manner,  and  in  the  blocks  displaced  as 
integers,  like  those  in  regions  having  the  Kaibab  and  other  structures,  from 
the  elevated  to  the  depressed  portions.  In  these  cases  the  cliffs  are  produced 
by  the  unequal  erosion  of  harder  and  softer  beds  wherever  upheaval  exceeds 
degradation,  and  climatic  conditions  are  favorable;  and,  further,  this  sap- 
ping process  is  carried  on  in  regions  of  great  declivity,  where  deep  channels 
of  corrasion  are  formed,  whatever  may  be  the  petrologic  conditions,  the 


192  STRUCTURAL   GEOLOGY. 

alternation  of  softer  and  harder  beds  not  being  an  absolute,  but  only  an 
accessory  condition.  In  those  mountain  regions  where  the  rocks  are  granites, 
schists,  or  extravasated  masses,  every  little  stream  engaged  in  deepening  its 
channel  furnishes  conditions  favorable  to  sapping;  and  so  these  walls  are  ever 
yielding,  in  small  fragments  that  tumble  down  from  time  to  time,  in  large 
fragments  when  cliffs  or  crags  topple  over,  and  in  great  masses  by  land 
slides.  So  wherever  cliffs  are  formed,  whether  by  deep  corrosion  or  unequal 
erosion,  the  cliffs  themselves  are  degraded,  disintegration  beginning  with  the 
breaking  of  the  rocks  above  through  atmospheric  causes,  aided  by  gravity. 
Then  the  rocks  are  transported  by  gravity  from  the  higher  to  lower  levels 
when  the  disintegration  is  increased  by  the  fall,  and  the  rocks  are  left  in  a 
condition  to  be  readily  transported  by  the  wash  of  rains  or  the  flow  of 
streams. 

The  extent  to  which  degradation  is  carried  on  by  this  sapping  though 
much  less  than  either  of  the  others,  is  so  great  that  it  must  not  be  neglected 
in  any  consideration  of  this  subject. 

In  a  mountain  region  every  stream  forms  cliffs  by  deep  corrasion,  and 
every  cliff  has  a  talus  in  evidence  of  the  efficiency  of  this  method,  and  we 
see  its  effects  exhibited  in  the  most  remarkable  manner  in  the  long  lines  of 
cliffs  or  towering  escarpments  which  stand  athwart  the  Plateau  Province. 

In  this  method  of  degradation  petrologic  conditions  may  be  more  or 
less  favorable,  but  within  these  conditions  the  principal  factor  in  determin- 
ing rate  of  degradation  is  declivity.  The  declivity  must  be  very  great  for 
the  initiation  of  the  process.  With  rocks  already  disintegrated  by  atmos- 
pheric agencies,  the  declivity  must  be  greater  than  what  is  usually  denomi- 
nated natural  slope  ;  that  is,  it  must  be  so  great  that  rock  power  can  Over- 
come friction  so  as  to  transport  the  material  to  a  lower  level ;  and  again, 
that  gravity  may  be  used  as  a  force  of  disintegration,  the  declivity  must  be 
still  further  increased,  and  with  this  increase  of  declivity  the  rate  of  dis- 

t/ 

integration  and  transportation  by  falling  is  increased  at  a  great  ratio  until 
the  rocks  are  undermined,  when  the  conditions  again  multiply  the  power. 
But  rapid  corrasion,  which  depends  on  declivity,  increases  sapping  ;  and 
sapping,  which  depends  on  declivity,  increases  corrasion  by  adding  to  the 


DEGRADATION.  193 

instrument  of  corrasion,  and  again  declivity  is  multiplied  as  a  factor  in 
degradation. 

To  this  rule  that  sapping  promotes  corrasion  by  adding  to  the  instru- 
ment of  corrasion,  there  are  three  curious  exceptions,  one  of  which  is  of 
great  importance.  The  first  is  where  the  cliff  produced  by  deep  corrasion, 
before  it  has  retreated  from  the  bank  of  the  stream,  tumbles  down  so  as  to 
choke  the  stream.  In  this  case  the  material  falling  from  the  cliffs  serves  to 
protect  the  underlying  stream  bed,  and,  so  far  as  it  ponds  the  water  up  stream, 
it  causes  it  to  precipitate  its  load,  and  thus  deprives  it  of  the  instrument  of 
corrasion.  But  this  fallen  matter  is  rapidly  attacked  by  the  stream,  is 
soon  taken  up  as  load,  and  used  as  an  instrument  of  corrasion. 

The  second  exception  is  where  a  lateral  stream  enters  a  main  one,  the 
lateral  stream  having  so  great  a  declivity  as  to  be  able  to  transport  great 
quantities  of  coarse  material  during  local  flood  time,  or  that  flood  time 
which  pertains  to  the  secondary  stream,  but  not  to  the  primary.  In  this 
case  it  may  sweep  along  its  greatly -inclined  bed  into  the  main  channel, 
load  derived  from  sapping,  or  even  from  erosion,  which  cannot  be  farther 
transported  by  the  main  stream,  and  this  new  matter  for  the  time  being 
serves  as  a  protection  to  the  bed  of  the  main  stream.  In  the  Colorado 
River,  with  very  few  exceptions,  all  the  falls  and  rapids  which  beset  its 
course  through  the  great  canons  are  caused  by  dams  made  by  side  streams 
having  great  declivity.  A  few  of  the  falls  are  made  by  dams  formed  by  the 
sapping  of  the  immediate  cliffs  of  the  main  river. 

The  third  exception  is  found  where  streams  having  great  declivity  run 
through  beds  of  incoherent  sands.  Here  load  is  rapidly  added  to  the  stream 
by  gravity,  and  the  stream  not  being  confined  by  water  tight  rocks,  its 
Abaters  penetrate  the  interstitial  spaces  of  the  sands  and  serve  to  overcome 
the  friction  of  slope,  and  thus  assist  rock  power  in  transporting  the  sand 
into  the  stream.  Here  the  stream  cannot  have  high  banks,  and  the  channel 
is  greatly  widened  and  is  engaged  in  transporting  load  furnished  it  from  the 
sides,  and  can  make  but  little  progress  in  corrasion,  for  every  particle  car- 
ried from  the  bottom  of  the  stream  is  rapidly  replaced  by  one  from  the 
sides.  This  condition  is  finely  illustrated  in  many  places  along  the  course 
of  the  Virgin  River,  a  tributary  of  the  Colorado.  In  one  place  where  its 
13  P  G 


194  STRUCTURAL    GEOLOGY. 

course  is  through  indurated  and  homogeneous  rocks,  its  channel  is  from  20 
to  50  feet  in  width,  and  from  1,500  to  3,000  feet  in  depth;  it  runs  through 
a  narrow  but  profound  gorge.  But  when  it  passes  a  well  defined  geologi- 
cal horizon  from  these  coherent  into  extremely  incoherent  beds,  its  channel 
abruptly  widens,  and  the  stream  is  a  broad  sheet  of  water  many  hundreds 
of  yards  in  width  and  but  a  few  inches  in  depth.  Again  this  condition  is 
well  illustrated  in  the  Platte  River  where  it  crosses  the  Plains.  Here  the 
beds  through  which  the  river  runs  are  incoherent,  and  although  the  river 
has  as  great  a  fall  as  the  Colorado  through  the  plateaus,  and  although  the 
climatic  conditions  are  essentially  the  same,  yet  the  former  runs  in  a  broad 
sheet  scarcely  below  the  level  of  the  plain,  while  the  latter  runs  in  a  narrow 
groove  at  profound  depths  below  the  general  surface.  Thus  it  is  that  the 
streams,  though  they  may  have  great  fall,  and  though  the  stream  beds  may 
be  of  material  that  can  be  rapidly  transported,  yet  they  do  not  succeed  in 
excavating  deep  channels,  for  every  particle  taken  from  the  bottom  is  re- 
placed. Nevertheless  general  degradation  is  carried  on  by  such  streams  at 
a  rapid  rate,  but  not  at  a  maximum  rate,  for  the  water  permeating  the  sands 
on  either  side  is  steadily  and  rapidly  evaporated,  and  is  thus  lost  as  an  agent 
of  degradation.  There  are  many  streams  in  the  arid  region  of  America, 
running  alternately  through  harder  and  softer  beds,  which  are  continuously 
degrading  the  coherent  rocks  and  intermittently  degrading  the  incoherent 
rocks ;  that  is,  the  streams  are  ever  living  where  the  beds  are  coherent,  but 
when  they  reach  the  sands  the  waters  sink  and  re-appear  where  the  beds 
below  are  harder.  Through  these  harder  beds  the  streams  caflon,  and 
through  the  softer  beds  low  plains  stretch  either  way  from  the  course  of 
the  stream  ; '  and  it  is  only  during  flood  time  that  the  channels  are  cut  across 
these  plains  from  canon  to  cailon. 

But  dropping  these  exceptions,  all  of  them  interesting  cases,  let  us  return 
to  the  main  argument.  We  have  seen  that  ever  are  the  effects  of  declivity 
in  degradation  multiplied  directly  and  indirectly.  Wherever  the  rate  of 
degradation  by  any  one  method  is  increased  it  is  due  chiefly  to  increased 
declivity,  and  wherever  the  rate  of  one  method  of  degradation  is  increased, 
the  rate  of  all  other  methods  is  increased. 

We  may  not  be  able  to  give  mathematic  expression  to  rate  of  degrada- 


DEGRADATION.  195 

tion  in  terms  of  declivity,  but  Hopkins  arid  Babbage  have  shown  that  the 
power  to  transport  load  of  a  given  size  of  particles  increases  with  the  sixth 
power  of  the  velocity  of  water,  and  it  is  probable  that  the  rate  of  degrada- 
tion increases  with  the  velocity  of  water  in  very  nearly  the  same  ratio,  but 
modified  slightly  by  a  multiplicity  of  climatic  and  petrologic  conditions. 

It  will  be  seen  that  in  the  above  discussion  I  have  neglected  one  term 
of  climate,  that  is  temperature.  My  field  of  study  has  been  limited,  to  the 
frigid  and  temperate  climates,  and  for  the  effect  of  a  torrid  climate  I  have 
no  facts  to  guide  me  to  valid  conclusions,  but  within  my  field  of  study  the 
temperature  term,  though  modifying  the  methods  and  topographic  results  of 
degradation,  does  not  invalidate  the  result  I  have  reached  as  to  the  over- 
shadowing importance  of  declivity.  Increased  cold  diminishes  the  protec- 
tion derived  from  vegetation  and  permits  greater  rainfall  to  produce  greater 
degradation.  But  in  a  given  latitude  increased  cold  is  due  to  increased  ele- 
vation. (This  increased  elevation  is  also  increased  declivity.)  But  this  i& 
again  modified  by  the  fact  that  moisture  descends  as  snow,  and  to  that  extent 
the  beating  power  of  rains  is  lost.  Where  these  snows  accumulate  as  ice, 
forming  glaciers,  another  modification  of  degradation  is  introduced,  dimin- 
ishing the  effects  of  the  water  in  degradation  and  changing  the  topographic 
features;  that  is,  any  given  amount  of  precipitation  of  water  will  produce 
more  degradation  acting  as  rains  and  rivers  than  as  snows  and  glaciers.  By 
the  former  condition  atmospheric  disintegration  is  more  rapid,  and  corrasion 
is  confined  to  narrower  channels,  and  thus  sapping  is  promoted.  Transporta- 
tion in  ice  and  water  are  governed  by  the  same  conditions  of  flotation,  and 
the  greater  heterogeneity  of  river  channel  promotes  greater  flotation,  so  that 
degradation  in  each  of  its  elements  of  disintegration  and  transportation  is 
faster  by  rains  and  rivers  than  by  snows  and  glaciers.  Hence,  as  cold 
increases,  degradation  is  promoted  by  the  decrease  of  protection  derived 
from  vegetation  until  that  degree  of  cold  is  reached  where  the  moisture  is 
precipitated  as  snow,  when  low  temperature  serves  to  decrease  degradation. 

Having  considered  all  the  modifying  conditions  of  climate  and  petrol- 
ogy, it  yet  remains .  that  degradation  increases  with  declivity  through  the 
combined  forces  of  water  power  and  rock  power  in  a  rapidly-multiplying 
rate  from  that  low  degree  of  declivity  which  permits  the  transportation  of 


196  STJRUCTUKAL  GEOLOGY. 

finely-comminuted  load  to  that  high  degree  of  declivity  which  permits,  the 
load  to  be  moved  by  its  own  gravity,  when  the  effect  of  declivity  is  again 
multiplied  at  a  still  higher  rate  until  vertically  is  reached  and  undermining 
begins  and  another  multiplication  of  the  effect  of  declivity  ensues. 

There  are  conditions  of  degradation  in  the  extremes  of  declivity  worthy 
of  mention.  In  high  degrees  of  declivity  transportation  in  a  horizontal 
direction  is  limited,  the  cliffs  soon  tumble  down,  and  degradation  by  this 
process  ceases.  In  a  very  low  degree  of  declivity  approaching  horizontally 
the  power  of  transporting  material  is  also  very  small.  The  degradation  of 
the  last  few  inches  of  a  broad  area  of  land  above  the  level  of  the  sea  would 
require  a  longer  time  than  all  the  thousands  of  feet  which  might  have  been 
above  it,  so  far  as  this  degradation  depends  on  mechanical  processes — that 
is,  driving  or  flotation;  but  here  the  disintegration  by  s.olution  and  the 
transportation  of  the  material  by  the  agency  of  fluidity  come  in  to  assist 
the  slow  processes  of  mechanical  degradation,  and  finally  perform  the  chief 
part  of  the  task. 

We  may  now  conclude  that  the  higher  the  mountain,  the  more  rapid  its 
degradation ;  that  high  mountains  cannot  live  much  longer  than  low  mount- 
ains, and  that  mountains  cannot  remain  long  as  mountains ;  they  are  ephem- 
eral Topographic  forms.  Geologically  all  existing  mountains  are  recent; 
the  ancient  mountains  are  gone.  But  existing  mountains  may  be  old  or 
young  as  compared  with  other  existing  mountains.  We  may  speak  of  the 
age  of  mountains,  referring  to  the  age  of  the  rocks  of  which  they  are  com- 
posed, but  this  will  have  no  reference  to  the  age  of  the  mountain  form.  We 
may  speak  of  the  age  of  a  mountain  with  respect  to  the  inception  of  the  up- 
heaval which  exposed  the  rocks  to  that  degradation  which  has  produced  the 
mountain  form;  and  this  epoch  will  not  be  very  long  ago,  geologically,  for 
the  rate  of  upheaval  must  be  greater  than  the  rate  of  degradation,  else 
mountain  forms  will  not  be  produced.  We  may  speak  of  the  age  of  mount- 
ains, referring  to  the  completion  of  the  upheaval  by  which  the  mountain 
forms  were  produced  through  degradation ;  the  time  which  has  elapsed  since 
the  epoch  to  which  we  then  refer  must  be  short  indeed;  but  if,  in  speaking 
of  the  age  of  mountains,  we  refer  to  the  time  when  those  topographic  forms 
were  produced,  they  are  all  newly  born. 


DEGEADATIOK .  107 

• 

Having  found  that  degradation  is  accelerated  by  increased  declivity  at 
a  high  rate,  let  us  apply  this  law  to  the  degradation  of  the  Uinta  uplift  and 
see  what  topographic  features  would  have  been  produced  if  the  uplift  had 
been  abrupt  or  greatly  faster  than  degradation.  As  the  area  was  uplifted 
in  large  part  as  an  integer,  its  steep  flanks  would  then  have  been  regions  of 
great  declivity,  while  its  axial  region  would  have  comparatively  gentle  slopes, 
and  as  the  first  streams  heading  along  the  axis  ran  toward  the  flanks,  these 
streams  would  not  only  have  had  channels  suddenly  increasing  in  declivity 
at  the  flanks,  but  the  amount  of  water  carried  by  the  streams  would  have 
steadily  increased  from  axis  to  flanks,  and  hence  corrasion  on  the  flanks 
would  have  proceeded  at  a  rate  determined  by  these  multiplied  causes.  As 
the  main  channels  were  thus  corraded  all  the  lateral  channels  would  in  like 
manner  have  been  rapidly  corraded ;  this  would  have  induced  rapid  sapping 
and  rapid  erosion,  and  the  degradation  along  the  flanks  would  have  far 
exceeded  degradation  along  the  axis,  and  this  would  have  resulted  in  the 
production  of  an  ever  narrowing  axial  ridge.  An  examination  of  the  map 
reveals  the  fact  that  these  are  not  the  topographic  characteristics  of  the 
Uinta  Mountains.  The  axial  region  is  higher  in  the  western  portion  of  that 
part  of  the  range  under  consideration,  but  the  difference  in  elevation 
between  the  flanks  and  axis  is  inconsiderable  when  compared  with  the  whole 
amount  of  degradation;  while  in  the  eastern  portion  of  the  part  of  the  range 
under  consideration  the  axial  region  is  much  lower  than  the  flanking  region 
on  either  side.  Here  the  excess  of  degradation  in  the  axial  region  is 
accounted  for  by  remembering  that  the  degradation  of  consequent  drainage 
has  been  assisted  by  the  degradation  resulting  from  extra  limital  or  through 
drainage.  But  in  the  former  case,  i.  e.,  the  western  portion  of  the  region 
under  consideration,  the  drainage  is  all  consequent  on  the  upheaval,  and  to 
account  for  the  plateau  like  character  of  the  region,  we  have  to  suppose 
either  that  the  elevation  being  constant  has  been  but  little  faster  than 
degradation ,  or  else  that  elevation  has  been  intermittent. 

O  ' 

Let  us  further  consider  these  two  hypotheses,  one  of  which  must  be 
true.  If  elevation  was  constant  but  slow,  the  axial  region  was  first  attacked 
by  degradation,  and  as  it  was  slowly  uplifted,  degradation  kept  this  axial 


198  STRUCTURAL  GEOLOGY. 

• 

region  down  so  that  an  axial  ridge  was  not  produced.  If  elevation  was 
intermittent  it  might  have  been  fast  for  a  time,  and  then  ceased  until  the 
region  was  planed  down  to  a  general  level  now  represented  only  by  the 
summits  of  the  highest  peaks,  and  then  a  new  upheaval  carried  it  to  its 
present  elevation.  But  the  rate  of  this  last  uplift  must  have  been  slow  or 
the  axial  ridge  would  have  been  more  pronounced,  and  hence  we  may  infer 
that  the  elevation  was  either  slow  by  continuous  motion,  or  what  would  be 
its  equivalent,  slow  through  intermission  of  movement,  with  the  last  epoch 
of  elevation  slow.  Further  light  will  be  thrown  on  this  subject  when  we 
consider  sedimentation.  It  is  manifest  that  if  elevation  was  slow  so  that 
degradation  progressed  nearly  as  fast  as  displacement,  then  degradation  was 
slow.  Again  consider  the  amount  of  degradation.  From  this  portion  of 
the  Uinta  range  a  block  three  and  one-half  miles  in  thickness  has  been 
carried  away,  all  since  the  close  of  Mesozoic  Age ;  and  for  this  degradation 
the  declivity  was  small  so  that  its  progress  was  slow,  and  we  have  some 
conception  of  the  amount  of  time  which  has  elapsed  since  the  beginning  of 
the  Uinta  upheaval. 

SCHOLIUM. 

Let  us  now  turn  aside  for  a  moment  from  the  main  argument  to  consider 
a  statement  which  I  have  elsewhere  made  concerning  the  Basin  Ranges.  These 
are  monoclinal  ridges  of  displacement,  of  narrow  base  and  steep  declivities 
where  conditions  for  rapid  degradation  obtain,  but  the  amount  of  degrada- 
tion of  any  Basin  Range  is  exceedingly  small  as  compared  with  the  Uinta 
Range,  and  we  are  forced  to  conclude  that  the  epoch  of  its  upheaval  is  much 
later  than  that  of  the  inception  of  the  Uinta  uplift,  but  may  be  of  about 
the  same  date  as  the  last  throw  of  the  Uinta  displacement. 

SEDIMENTATION. 

Soon  after  the  inception  of  this  upheaval,  sedimentation  began  on  either 
flank  and  continued  during  the  progress  of  the  uplift  until  on  the  north 
side  more  than  6,000  feet  of  sandstones  and  shales  had  been  deposited,  and 
where  the  Brown's  Park  beds  overlap  Bridger  beds  about  8,000  feet.  On 
the  south  side  also  there  was  a  great  accumulation,  the  extent  and  charac- 


SEDIMENTATION.  199 

teristics  of  which  are  not  yet  fully  known.  Geologists  will  understand  that 
the  thicknesses  given  refer  only  to  the  beds  which  remain  to  be  studied. 
There  may  have  been  much  greater  sedimentation ;  beds  may  have  been 
formed  during  periods  of  sedimentation  which  were  carried  away  during 
periods  of  dry  land  conditions,  and  especially  during  the  last  great  period 
of  degradation  not  yet  ended,  and  of  which  sediments  there  are  no  residuary 
fragments  attesting  to  their  former  existence. 

On  both  sides  of  the  range,  but  especially  to  the  north,  we  know  that 
the  progress  of  sedimentation  was  interrupted  by  periods  of  dry  land  con- 
ditions. These  dry  land  conditions  prevailed  over  a  large  area  during  the 
epoch  separating  the  Lower  Green  River  from  the  Bridger  period,  but  a 
part  of  this  interval  of  time  at  least  was  occupied  in  sedimentation  over  a 
portion  of  the  great  lacustrine  area.  Again,  a  period  of  dry  land  con- 
ditions prevailed  between  the  deposition  of  the  Bridger  and  the  Brown's 
Park  Groups.  The  latter  was  deposited  over  areas  in  the  region  of  uplift 
beyond  the  reaches  of  the  antecedent  lakes  represented  by  the  four  lower 
Cenozoic  groups.  How  far  the  Brown's  Park  Lake  extended  over  the  region 
which  had  previously  been  occupied  by  the  waters  in  which  the  earlier 
Tertiary  sediments  were  deposited  we  do  not  know.  Wherever  the  overlap 
of  the  Brown's  Park  beds  on  the  Lower  Cenozoic  groups  has  been  studied 
the  former  terminate  in  escarpments,  and  no  evidence  of  shore  line  has  been 
seen.  The  Bishop  Mountain  Conglomerate  which  has  been  found  to  lie  uncon- 
formably  on  all  the  other  geological  formations  of  this  region,  except  the 
Brown's  Park,  and  possibly  on  this  latter  also,  is  neither  a  marine  nor 
lacustrine  deposit,  but  is  believed  to  be  a  subaerial  gravel.  It  is  possible 
many  geologists  would  ascribe  it  to  the  action  of  ice,  but  in  any  case  it  need 
not  be  considered  in  our  account  of  sedimentation. 

Such  were  the  general  changes  from  emergence  to  submergence  through- 
out the  region  of  downthrow,  but  there  was  a  narrow  belt  of  country  between 
the  general  region  of  uplift  and  the  general  region  of  downthrow  which 
was  subject  to  more  frequent  changes  than  the  greater  ones  described  above. 

We  find,  first,  that  there  are  many  overlaps,  i.  e.,  that  later  beds  extend 
beyond  the  limits  of  earlier  beds.  To  accomplish  this  result  it  is  manifest 
that  the  waters  of  the  lakes  must  have  risen  or  the  land  subsided.  Again, 


200  STEUCTUEAL  GEOLOGY. 

we  find  that  certain  beds  thin  out  shoreward.  It  is  manifest  in  this  case 
that  the  waters  of  the  lakes  must  have  fallen  or  the  land  have  risen.  Again, 
we  find  upper  lake  beds  unconformable  on  lower  lake  beds.  Here  it  is 
manifest  that  a  dry  land  period  separated  their  deposition,  and  that  displace- 
ment occurred.  These  outthinnings,  overlappings,  and  unconformities 
appear  from  time  to  time  from  the  base  to  the  summit  of  all  the  fresh  water 
beds  older  than  the  Brown's  Park. 

There  are  some  other  interesting  facts  relating  to  the  belt  under  con- 
sideration, viz,  the  appearance  of  many  conglomerates  which  are  rapidly 
changed  into  sandstones  in  a  direction  farther  from  shore.  These  conglom- 
erates are  found  to  be  made  up  of  the  more  or  less  water-worn  fragments  of 
limestones,  sandstones,  and  quartzites  similar  to  those  outcroppings  in  the 
mountain  region  or  area  of  uplift,  and  often  contain  the  same  fossils,  leading 
us  to  conclude  that  they  are  derived  from  that  region. 

It  should  be  remarked  here  that  the  appearance  of  these  conglomerates, 
together  with  the  overlappings,  outthinnings,  and  unconformities  before 
mentioned,  furnish  the  evidence  on  which  we  decide  that  this  was  the  old 
shore-line,  and  that  the  lake  beds  were  never  continuous  over  the  great 
Uinta  area.  On  the  other  hand,  the  fact  that  no  such  phenomena  have  been 
observed  in  the  outcroppings  of  the  Mesozoic  and  Paleozoic  beds  leads  us  to 
conclude  that  they  were  at  one  time  continuous  over  the  Uinta  area,  and 
this  is  strengthened  by  the  fact  that  in  all  these  lower  groups  any  bed  found 
on  the  one  flank  re-appears  on  the  other  with  all  its  lithologic  character- 
istics; and  it  is  thus  that  we  fix  the  epoch  of  the  inception  of  the  Uinta 
upheaval  after  the  close  of  the  deposition  of  the  Upper  Hogback  Sandstone 
of  the  Point  of  Rocks  Group,  and  before  the  deposition  of  the  lowest  bed 
of  the  Bitter  Creek  formation. 

Returning  again  to  the  consideration  of  sedimentation  in  the  region  of 
downthrow  in  its  relation  to  displacement  and  degradation  in  the  region  of 
uplift,  we  have  first  to  consider  the  amount  of  sedimentation  or  building  up 
of  the  sediments  on  the  flanks  of  the  uplifts  to  the  extent  of  many  thousand 
of  feet ;  next,  the  general  unconformities  which  separate  some  of  the  forma- 
tions ;  and,  lastly,  the  minor  unconformities,  overlappings,  and  outthinnings 
observed  in  the  zone  of  ancient  shore-lines.  From  all  these  facts  it  appears 


UINTA  MOUNTAINS— RECAPITULATION.  201 

that  displacement,  degradation,  and  sedimentation  were  in  a  general  way 
simultaneous  and  continuous  up  to  the  close  of  the  Bridger  period,  but 
interrupted  by  many  minor  cessations  in  the  progress  of  displacement  and 
some  cessations  in  the  progress  of  deposition,  and  that  between  the  Bridger 
and  Brown's  Park  periods  there  was  a  long  time  when  no  sediments  were 
accumulated. 

The  Uinta  uplift  in  the  region  of  Brown's  Park  was  at  one  time  several 
thousand  feet  greater  than  we  have  represented  it  to  be,  but  after  the  deposi- 
tion of  the  Brown's  Park  beds  it  fell  down  that  much ;  the  evidence  of  this 
will  more  fully  appear  when  we  have  discussed  the  Yampa  plateau,  Diamond 
Peak,  the  Dry  Mountains,  and  Brown's  Park. 

RECAPITULATION. 

We  will  now  recapitulate  some  of  the  important  conclusions  reached 
in  the  study  of  the  geology  of  the  Uinta  Mountains.  First,  the  upheaval 
began  at  the  close  of  the  Mesozoic  Age,  and  continued  with  slight  intermis- 
sions until  after  the  Bridger  period,  and  the  total  amount  of  upheaval  in  the 
axial  region  was  more  than  30,000  feet.  The  region  was  upheaved  partly  as 
an  integer  and  partly  as  a  body  of  minute  parts.  Second,  pari  passu  with 
upheaval  degradation  progressed,  and  in  some  places  along  the  axial  portions 
of  the  region  this  degradation  amounts  to  more  than  25,000  feet,  and  the 
mean  degradation  is  three  and  one-half  miles,  and  from  the  entire  area  there 
has  been  a  total  degradation  of  7,095  cubic  miles.  While  we  have  no 
means  of  determining  any  absolute  rate  of  degradation,  we  are  led  to  con- 
clude that  a  maximum  rate  was  not  established ;  that,  as  upheaval  was  slow, 
degradation  was  slow.  Third,  pari  passu  with  displacement  and  degrada- 
tion in  the  region  of  uplift,  there  was  sedimentation  in  the  region  of  down- 
throw. This  sedimentation  was  sometimes  intermittent  over  large  areas, 
frequently  intermittent  along  the  shore-line  zones.  These  sediments  were 
derived  in  part  at  least  from  the  region  of  uplift,  but  probably  mingled  with 
materials  brought  from  districts  not  embraced  in  the  region  under  discussion. 
On  the  north  side  of  the  mountains  the  amount  of  sedimentation  was  more 
than  6,000  feet,  and  where  the  Brown's  Park  beds  overlap  Bridger  beds  the 
amount  of  sedimentation  was  about  8,000  feet. 


202  STKUCTUKAL  GEOLOGY. 

THE  YAMPA  PLATEAU. 
DISPLACEMENT. 

The  structural  sections  of  Plate  I  embrace  not  only  the  Uinta  Mountain 
region,  but  also  extend  over  the  region  which  I  have  designated  as  the  Yampa 
Plateau.  The  facts  relating  to  the  present  position  of  the  formations  are 
there  fully  set  forth.  On  Plate  V  we  have  separated  the  stereogram  of  the 
Yampa  region  from  the  general  stereogram,  Plate  III.  Referring  to  Plate 
V,  attention  is  called  to  the  Island  Park  sag  d,  d,  to  the  Echo  Park  sag  e, 
to  the  Split  Mountain  cusp  c,  to  the  monoclinal  flexure  of  Cliff  Creek  m,  m, 
w,  to  the  Fox  Creek  flexure  f,  and  to  the  Yampa  fault  #,  g,  which  branches 
midway  in  its  course. 

A  comparison  of  'this  stereogram  with  the  geological  map  will  be 
instructive. 

The  Yampa  Plateau  is  on  the  south  side  of  the  Uinta  Mountains,  and 
all  the  lines  of  displacement  in  the  stereogram,  except  the  Y ampa  fault,  show 
the  upheaval  to  be  northward  corresponding  to  the  general  upheaval  of  the 
Uinta  Mountains,  but  the  exception  mentioned  exhibits  a  northward  throw. 
This  great  displacement  is  a  flexure  at  its  eastern  end ;  but  it  finally 
changes  into  a  dragged  fault,  where  the  thrown  beds  are  flexed  upward  at 
the  end,  and  then  into  a  clean  fault ;  midway  in  its  course  it  branches ;  the 
northern  branch  is  a  fault  as  far  as  it  has  been  traced ;  the  southern  branch 
changes  from  a  fault  to  a  monoclinal  flexure,  and  finally  these  branches  of 
the  great  displacement  fade  out,  but  in  a  manner  not  clearly  understood,  as 
the  region  is  marked  by  an  accumulation  of  late  subaerial  gravels,  by  soil 
and  by  vegetation,  and  on  the  stereogram  this  uncertain  area  has  been  rep- 
resented by  broken  lines.  By  referring  to  the  map  it  will  be  seen  that  the 
main  fault  with  its  branches  is  represented  in  the  topography  of  the  country 
by  bold  cliffs.  These  lines  of  cliffs  are  broken  by  many  deep  gorges  of 
corrasion  descending  from  the  plateau  to  the  lowlands  where  the  stratigraphy 
is  plainly  revealed,  and  the  lower  beds  of  Triassic  sandstone  are  seen  on 
the  same  geographic  level  as  the  upper  beds  of  Uinta  Sandstone,  so  that  the 
total  displacement  is  about  5,000  feet.  These  cliffs  are  due  immediately  to 


THE  YAMPA  PLATEAU.  203 

displacement ;  where  this  displacement  is  by  faulting  the  cliffs  are  escarp- 
ments, but  where  it  is  by  flexure  the  flexed  beds  remain,  and  the  slope  of 
the  cliffs  conforms  in  a  general  way  with  the  dip  of  the  strata.  Hence  these 
lines  of  cliffs  have  not  receded  from  the  locus  of  displacement,  although  they 
are  so  precipitous  as  so  furnish  conditions  favorable  to  rapid  degradation  by 
direct  sapping,  corrasion,  and  general  erosion.  From  these  facts  we  inevi- 
tably conclude  that  the  displacement  is  of  late  date.  But  the  Triassic  beds 
on  the  upheaved  side  are  gone,  and  in  many  places  a  great  thickness  of 
Carboniferous  beds  also,  while  on  the  thrown  side  a  notable  thickness  of 
Trias  yet  remains.  The  non-recession  of  the  cliffs  proves  that  the  displace- 
ment was  not  ended  long  ago,  if  indeed  the  movement  has  yet  ceased,  while 
the  occurrence  of  the  beds  on  the  thrown  side,  which  have  been  degraded 
from  the  upheaved  side,  lead  us  to  refer  the  inception  of  the  upheaval  to  an 
epoch  of  much  earlier  date,  and  to  infer  that  the  displacement  was  slow,  yet 
not  so  slow  that  degradation  was  able  to  keep  apace. 

When  we  come  hereafter  to  discuss  the  relation  of  this  displacement  to 
Other  facts  of  displacement,  degradation,  and  sedimentation,  it  will  appear 
that  this  displacement  was  not  upheaval  in  relation  to  the  general  region 
under  discussion  in  this  chapter,  but  was  in  fact  downthrow,  whatever  it 
might  have  been  in  relation  to  the  level  of  the  sea  or  in  that  other  relation, 
which  yet  may  be  a  very  different  thing,  i.e.,  to  the  center  of  the  earth. 

SCHOLIUM. 

Early  in  this  volume  I  distinctly  defined  my  use  of  the  terms  "upheaval" 
"subsidence,"  "uplift,"  and  "downthrow,"  and  restricted  the  meaning  of  these 
words  in  such  a  manner  that  they  should  relate  only  to  adjacent  and  compared 
beds  of  rock,  but  I  recognize  three  categories  of  relations  that  may  be 
expressed  by  these  terms,  viz,  the  relation  of  parts  of  a  geological  horizon 
to  each  other,  the  relation  of  parts  of  a  geological  ho'rizon  to  the  level  of 
the  sea,  and  the  relation  of  parts  of  a  geological  horizon  to  the  center  of 
the  earth.  For  these  several  categories  it  would  be  a  great  advantage  to 
geological  science,  by  leading  to  greater  simplicity  and  precision  of  de- 
scription and  to  clearer  conceptions,  if  different  verbal  representatives  could 
be  used  for  the  different  ideas. 


204  STRUCTURAL  GEOLOGY. 

DEGKADATION. 

The  amount  of  degradation  in  the  region  of  the  Yampa  Plateau  though 
less  than  in  the  Uinta  region  as  denned  above,  is  still  great.  The  maximum 
degradation  is  found  at  the  few  points  where  deep  canons  cut  the  cliffs  of 
the  Yampa  fault,  and  Uinta  Sandstone  is  found  in  the  floor.  In  these  places 
there  has  been  more  than  15,000  feet  carried  away  since  the  close  of 
Mesozoic  time ;  the  mean  degradation  over  the  entire  area  has  been  8,000 
feet,  or  a  little  more  than  one  and  a  half  miles,  and  the  total  more  .than 

1,200  cubic  miles. 

SEDIMENTATION. 

A  part  of  the  rock  material  taken  from  this  region  was  doubtless 
deposited  in  the  Tertiary  lake  region  to  the  south,  another  portion  probably 
into  the  BroAvn's  Park  Lake,  and  still  another  and  very  considerable  portion 
has  been  carried  away  by  the  Colorado  River  to  the  distant  sea. 

JUNCTION  MOUNTAIN. 

This  district  was  studied  in  the  earlier  years  of  the  exploration  of  the 
region,  and  since  that  time  it  has  not  been  carefully  reviewed.  In  my  notes 
I  make  mention  of  a  fault  running  in  a  north  and  south  direction  to  the  east 
of  the  axis  of  upheaval,  with  a  throw  to  the  westward,  but  the  magnitude 
and  general  characteristics  of  the  fault  are  not  given.  The  sections  given 
in  Chapter  I  of  this  volume,  figures  1  and  2,  represent  the  idea  of  its  structure 
obtained  at  the  time  it  was  studied,  but  subsequent  years  of  observation  in 
other  regions  lead  me  to  place  no  great  value  on  the  observations  made 
and  conclusions  reached  at  that  time. 

DIAMOND  PEAK. 

To  the  north  of  0-wi-yu-kuts  Plateau  is  Diamond  Peak.  The  principal 
mass  of  the  mountain  is  on  the  north  side  of  the  great  Uinta  fault,  but  the 
foot  of  the  mountain  stretches  across  from  the  thrown  to  the  upheaved  side 
of  the  fault. 

For  a  long  time  this  mountain  was  an  enigma.     From  its  position  it 


DIAMOND  PEAK. 

ought  to  be  a  monoclinal  ridge,  but  it  is  not.  Again,  its  base  rises  chiefly 
from  the  thrown  side  of  the  fault,  but  its  summit  rises  many  hundreds  of 
feet  higher  than  the  plateau  on  the  upheaved  side  of  the  fault,  and  it  seems 
to  stand  as  a  contradiction  to  all  known  laws  of  the  progress  of  degrada- 
tion. On  a  first  visit  to  the  mountain  no  clew  to  this  enigma  was  obtained ; 
on  a  second  visit  a  better  understanding  of  its  lithologic  constitution  was 
obtained;  and  on  a  third  and  final  visit,  which  was  somewhat  protracted,  it 
is  believed  that  the  problem  was  solved. 

All  that  portion  of  the  base  of  the  peak  north  of  the  fault  is  composed 
of  beds  of  the  Bitter  Creek  period  lying  horizontally.  On  the  horizontal 
beds  sandstones  and  limestones  are  piled  in  confusion.  In  the  sandstones 
no  fossils  were  found,  but  they  resemble  lithologically  the  sandstones  of 
Carboniferous  Age.  The  limestones  contain  Carboniferous  fossils.  We 
have  in  fact  a  huge  pile  of  Carboniferous  rocks  resting  on  a  base  of  horizon- 
tal Tertiary  sandstones.  Now  to  explain  how  rocks  of  an  older  horizon 
were  piled  on  a  later,  w^e  have  a  fact  which  was  discovered  after  the  second 
visit,  but  before  the  third,  viz,  that  there  had  been  two  movements  along 
the  line  of  this  fault  in  opposite  directions.  By  the  first  movement  the 
Uinta  or  upheaved  side  was  earned  about  3,000  feet  higher  in  relation  to 
the  beds  on  the  north  side  than  now  appears.  Subsequently  by  a  reverse 
movement  it  fell  back  the  3,000  feet.  After  the  former  displacement  and 
before  the  latter,  we  may  reasonably  suppose  that  here  a  great  cliff  faced 
northward,  for  the  total  displacement  by  faulting  was.about  23,000  feet,  and 
the  only  hypothesis  necessary  to  the  explanation  of  such  a  line  of  cliffs  is  that 
displacement  was  in  its  later  development  faster  than  degradation.  Such 
cliffs  would  rapidly  tumble  down,  and  beds  of  Carboniferous  Age  might 
thus  be  placed  on  beds  of  Tertiary  Age.  But  further,  immediately  to  the 
west  and  immediately  to  the  east  along  this  zone  of  displacement,  the  line 
of  faulting  in  its  meanders  back  and  forth  through  the  zone  of  flexure, 
which  has  heretofore  been  described,  passes  some  distance  from  the  upheaved 
side  of  the  zone  toward  the  thrown  side,  and  hence  the  beds  on  the  upheaved 
side  dip  at  a  great  angle  to  the  northward,  and  are  in  a  position  to  more 
readily  tumble  down,  and  doubtless  this  condition  obtained  where  the 


200  STRUCTURAL  GEOLOGY. 

0-wi-yu-kuts  cliff  overhung  the  Tertiary  sandstones  that  form  the  base  of 
Diamond  Peak. 

This  double  movement  along  the  plane  of  the  Uinta  fault  is  seen 
farther  west  beyond  Red  Creek,  where  it  was  first  discovered,  and  where 
the  sandstones  of  the  Point  of  Rocks  period  are  found  to  have  been 
dragged  down  by  the  later  arid  southward  throw.  Similar  evidences  are 
seen  farther  eastward,  between  Diamond  Peak  and  Red  Creek,  and  the 
topographic  features  of  the  region  in  like  manner  give  evidence  of  the 
later  movement,  for  some  of  the  peaks  composed  of  Bitter  Creek  sand- 
stones are  higher  than  the  mountains  and  plateaus  of  quartzite  and  Uinta 
Sandstone.  To  the  east  of  Diamond  Peak  this  second  displacement  did 
not  follow  the  old  plane  of  faulting,  but  trended  irregularly  northward 
and  bent  downward  the  edges  of  the  beds  which  originally  abutted  against 
the  southern  wall  of  the  fault,  which  was  composed  of  Uinta  Sandstone  and 
underlying  rocks.  Subsequent  degradation  has  earned  away  the  upper 
part  of  these  beds  that  were  turned  down,  and  we  now  see  fragments 
standing  on  edge  and  the  younger  beds  are  on  the  south  side,  the  older 
beds  on  the  north  side,  a  fact  which  I  have  stated  in  a  former  chapter,  and 
which  is  thus  explained.  But  we  have  still  further  evidence  of  this  later 
throw  on  the  south  side.  The  beds  of  the  Brown's  Park  Lake  were 
deposited  against  the  foot  of  Diamond  Peak,  and  this  later  displacement 
was  subsequent  to  the  deposition  of  these  beds,  and  the  plane  of  faulting 
cuts  them  in  twain.  Those  fragments  on  the  north  side  of  the  fault  lie 
high  upon  the  side  of  Diamond  Peak,  while  the  beds  on  the  south  side  of 
the  fault  are  low  down  in  the  valley  at  the  foot  of  the  peak.  The  latter 
are  nearly  horizontal ;  the  former  have  a  general  dip  southward,  but  are 
broken  and  greatly  contorted. 

This  mountain,  of  origin  so  strange,  was  curiously  enough  the  scene 
of  the  great  diamond  bubble,  so  skillfully  burst  by  my  brother  geologist, 
Clarence  King. 

THE  DRY  MOUNTAINS. 

This  low  range  of  mountains  extends  in  a  southeasterly  direction  from 
Vermilion  Creek  to  the  Snake  River,  and,  topographically,  appears  to  be  a 


THE  DKY  MOUNTAINS.  207 

continuation  of  the  great  monoclinal  ridge  of  Carboniferous  sandstone  north- 
east of  Po  Canon,  but,  in  fact,  these  mountains  are  made  up  of  beds  of  Ter- 
tiary Age,  though  there  are  outcrops  of  Mesozoic  beds  in  the  depths  of  the 
deeper  gulches. 

This  range  marks  the  continuation  of  the  displacement  that  I  have 
called  the  great  Uinta  fault,  and  the  evidences  of  the  reverse  movement  are 
complete.  The  first  movement,  which  was  upheaval  on  the  Uinta  side  and 
throw  on  the  northeast  side,  seems  to  have  been  by  monoclinal  flexure, 
while  the  last  movement,  which  was  throw  on  the  Uinta  side  and  upheaval 
on  the  northeast  side,  was  in  part  by  flexure  and  in  part  by  fracture.  But 
in  the  period  of  time  separating  the  two  movements  the  Brown's  Park  beds 
were  deposited  across  the  zone  of  original  flexure  which  had  been  greatly 
degraded;  still  farther  to  the  north  west  there  is  another  line  of  displacement 
approximately  parallel  to  the  first,  with  its  throw  also  on  the  southwest  side, 
corresponding  in  this  respect  with  the  throw  of  the  last  displacement  in  the 
Dry  Mountain  district.  This  northeast  displacement  fades  out  in  a  northwest 
direction,  and  entirely  disappears  at  the  divide  between  the  water-shed  of 
the  Vermilion  and  the  water-shed  of  the  Snake  River.  When  it  is  first  seen 
near  this  divide  it  is  a  gentle  monoclinal  flexure,  and  steadily  increases  in 
abruptness  along  its  line  in  a  northeasterly  direction  until  the  bluffs  of  the 
Snake  River  are  reached,  where  it  is  seen  as  a  dragged  fault.  There  seems 
to  be  no  doubt  that  these  displacements  having  throws  to  the  southwest  were 
synchronous,  while  the  evidence  that  the  monoclinal  flexure  with  throw  to 
the  northeast  was  of  earlier  date  is  complete,  for  between  the  two  periods 
the  Brown's  Park  beds  were  deposited — that  is,  the  Brown's  Park  beds  are 
seen  to  have  been  involved  in  the  displacement  having  a  southwest  throw, 
but  took  no  part  in  the  displacement  with  a  northeast  throw,  as  this  last  dis- 
placement was  made  and  the  beds  involved  in  it  were  truncated  prior  to  the 
deposition  of  the  Brown's  Park  beds,  and  these  beds  were  placed  over  their 
upturned  edges. 

In  the  Dry  Mountains  some  interesting  facts  have  been  observed. 
Along  or  near  to  the  line  of  double  or  reverse  displacements  we  sometimes 
find  an  escarpment  facing  the  southwest,  composed  of  beds  of  the  Bridger 
period,  or  of  still  lower  Cenozoic  rocks,  and  dipping  back  toward  the  north- 


208  STRUCTURAL  GEOLOGY. 

east,  but  as  often  we  find  escarpments  facing  the  northeast  composed  of 
beds  of  the  Brown's  Park  period,  horizontal  or  gently  dipping  to  the  south- 
west, i.  e.,  the  escarpments  of  this  range  are  sometimes  reversed,  because  of 
the  reverse  movement  along  the  planes  of  fracture  or  the  zone  of  flexure. 

BROWN'S  PARK. 

In  this  discussion  I  shall  not  only  include  Brown's  Park  proper,  but  a 
district  of  country  stretching  to  the  southwest,  between  the  Dry  Mountains 
and  Escalante  Peaks  to  the  Snake  River.  Here  we  have  a  geological  basin 
with  a  floor  of  Uinta  Sandstone  and  Carboniferous  and  Mesozoic  rocks.  Its 
longest  diameter  is  in  the  same  direction  as  the  axis  of  the  Uinta  uplift,  and 
while  the  basin  extends  somewhat  southward  across  the  axis,  yet  the  larger 
part  of  the  basin  is  on  the  north  side  of  the  axis.  But  the  old  lake  basin 
extended  eastward  and  northward  far  beyond  the  area  included  in  the  Uinta 
uplift  and  beyond  the  present  channel  of  the  Snake  River,  and  here  the  floor 
is  unknown ;  but  this  latter  region  is  not  within  the  limits  of  present  discussion. 

Within  the  region  under  discussion  on  the  floor  of  the  old  lake  basin 
beds  of  the  Brown's  Park  period  were  deposited;  these  beds  lie  chiefly  in  a 
horizontal  position,  but  on  the  north  side  of  Brown's  Park  the  beds  are 
abruptly  turned  up  against  the  Uinta  Sandstone  of  the  O-wi-yu-kuts  Plateau, 
with  a  dip  of  about  twenty-five  degrees.  Farther  to  the  east,  near  the  divide 
between  the  waters  of  the  Green  and  the  Snake,  south  of  the  monoclinal 
flexure  and  fault  of  the  Dry  Mountains,  a  deep  synclinal  flexure  is  observed; 
parallel  with  it  and  still  farther  south  another  of  less  magnitude,  and  still 
beyond  a  third  but  slightly  developed. 

Let  us  now  consider  the  effect  which  the  reverse  throw  along  the  great 
Uinta  fault  and  the  throw  along  the  Yampa  fault  has  had  on  this  valley. 
In  the  former  the  downthrow  at  Red  Creek  is  perhaps  less  than  1,000  feet; 
at  Diamond  Peak,  about  3,000  feet;  and  the  total  throw  of  the  two  displace- 
ments in  the  Dry  Mountains  and  vicinity  is  probably  more  than  4,000  feet. 
The  throw  of  the  Yampa  fault,  from  its  inception  on  the  west,  soon  attains 
a  magnitude  of  5,000  feet,  and  where  it  is  lost  by  transverse  structure,  near 
Junction  Mountain,  it  is  about  3,000  feet.  Thus  it  is  seen  that  the  great 
block  between  these  two  faults  lias  fallen  down  from  1,000  to  5,000  feet  in 


BROWN'S  PARK— ASPEN  MOUNTAIN  DISTRICT.  209 

its  different  portions.  Prior  to  this  downthrow  there  was  a  great  elevated 
valley  drained  into  the  Green  River.  When  the  downthrow  commenced  it 
is  probable  that  the  Brown's  Park  beds  were  not  yet  deposited,  but  after  it 
had  continued  for  some  time  the  region  was  so  depressed  that  the  waters  of 
the  stream  were  ponded  and  a  lake  formed.  In  this  lake,  then,  the  Brown's 
Park  beds  were  accumulated. 

We  know  that  the  Brown's  Park  beds  were  involved  in  a  part  at  least 
of  this  downthrow,  and  hence  were  deposited  before  the  downthrow  was 
accomplished,  because  the  beds  themselves  were  involved  in  the  displace- 
ment; they  are  severed  by  faults  and  bent  by  fractures  where  they  are  seen 
to  overlap  or  extend  beyond  the  area  of  downthrow. 

Hence  it  is  seen  that  Brown's  Park  is  not  a  valley  of  displacement 
o'r  of  subsidence,  but  was  originally  formed  as  a  valley  of  degradation — an 
elevated  valley  in  a  mountain  region.  It  subsided  or  fell  down  as  a  part  of 
a  greater  block.  But  the  whole  of  it  did  not  thus  subside,  for  the  Dry  Mount- 
ain's stand  across  the  site  of  this  ancient  depression. 

ASPEN  MOUNTAIN  DISTRICT. 

In  this  district  we  have  a  great  upheaval  with  its  axis  in  a  north  and 
south  -direction,  at  right  angles  to  the  Uinta  upheaval.  On  either  side  of 
the  upheaval  there  are  zones  of  maximum  flexure. 

The  beds  brought  to  view  in  the  degradation  of  this  upheaval  are  all 
the  Cretaceous  formations  above  the  Henry's  Fork  Group  and  all  the  Cenozoic 
groups  below  the  Brown's  Park;  hence  the  inception  of  this  upheaval  dates 
from  some  epoch  in  Post-Bridger  time.  The  whole  of  the  uplift  is  not  within 
the  area  embraced  in  the  map.  The  section,  together  with  the  geological 
map,  presents  all  the  important  characteristics  of  this  uplift,  but  there  are 
some  minor  features  of  interest.  In  the  northwest,  northeast,  and  southeast 
angles  or  corners  of  the  uplift  there  are  many  minor  faults  normal  to  the 
strike  of  the  beds.  Quien  Hornet  Mountain  stands  on  the  southwest  corner. 
No  faults  have  been  discovered  here. 

There  is.  a  gentle  synclinal  between  the  end  of  the  Aspen  Mountain 
uplift  and  the  side  of  the  Uinta  uplift.  At  the  south  end  of  the  uplift  the 

axis  passes  through  the  eastern  end  of  Aspen  Mountain.      Farther  north- 
14  P  o 


210  STRUCTURAL  GEOLOGY. 

ward  the  axial  region,  topographically,  is  a  valley,  for  Bitter  Creek  divides 
the  uplift,  a  stream  having  an  extra  limital  source— a  stream  whose  course 
was  determined  antecedent  to  the  uplift. 

In  the  heart  of  the  uplift  Cretaceous  beds  of  extreme  friability  are  found, 
and  the  secondary  drainage  or  lateral  wet-weather  tributaries  to  Bitter  Creek 
have  excavated  these  valleys  to  the  very  heart  of  the  uplift. 

Here  10,000  feet  of  beds  have  been  carried  away  by  the  waters  since 
the  inception  of  the  uplift. 


INDEX. 


Pago. 

Amplexus  zaphrentiformis 107 

Anchura  prolabiata . 121 

ruida 120 

Anticlinal  Structure v 10,17,24 

Appalachian  Mountains ." 24 

Structure 9,24 

Area  Coalvillensis 115 

Archajocidaris  cratis 109 

Avicula  Parkeusis 115 

Aspen  Mountain '      160 

district 153 

,  Structure  of 209 

Bannister,  Dr.  H.  M 48 

Basin  Province 6, 7, 29 

,  Orograpbic  structure  of ". 23 

,  Summary  of  history  of. 32 

Ranges 6,24 

,  Sedimentary  rocks  of 8 

Range  Structure 16,17,19,24,29 

Bellerophon  carbonarius  Cox,  var.  snbpapillosus 92 

Bishop  Mountain  Conglomerate,  Distribution  of 169 

relations 62,165,170,199 

type  localities 44 

Bitter  Creek  Group,  Distribution  of , 162 

Delations 64,162 

,  type  localities 45 

Black  Butte 160 

Quartzito 160 

Blake,  Prof.  VV.  P.,  on  the  Plateau  Province 3 

Bridger  Group,  Distribution  of 167 

,  Fossils  of 105 

,  relations 63,167,199 

,  type  localities 45 

Brown's  Park  Group,  Distribution  of 168 

,  relations 63,199,208 

,  Structure  of 208 

Group,  type  localities 44 

Bruce  Mountain 163 

Butte,  Black * 160 

,  Pilot 18,25 

Buttes 15 

Cameo  mountains 15 

Cameo  Mountains 15 

Structure 15 

211 


212  INDEX. 

Page. 

Camptonectes  platessiformis 93 

Canon  of  Desolation,  Later  views  on  fossils  from IX 

Carboniferous  Period,  fossils  of 88 

Catalogue  of  fossils 88 

Cliffs  of  Displacement  14 

Erosion : 15 

Colorado  River 193 

Conformity  of  the  Cretaceous 15(5 

Cope,  Prof.  E.  D.,  on  separation  of  Tertiary  and  Cretaceous 72 

Washiki  Group G5, 156 

Corbicula  Powelli 127 

Corbnla  snbtmdifera 129 

Corrasion 189 

Correlation  of  Cretaceous  and  Tertiary  Groups 71 

Cretaceous  Period,  fossils  of 94, 101 

Cyrena  (Veloritina)  erecta 117 

Declivity  as  a  condition  of  degradation 184,186,187,189,192,195,197 

Descriptions  of  new  species  of  fossils 107 

Degradation 182 

,  Methods  of 188 

of  the  Uiuta  Mountains „ 181 

Desolation,  Canon  of,  Later  views  on  fossils  from; T IX 

Diamond  Peak 164 

Structure  of 204 

Disintegration : 182 

Dynamics  of 183 

Displacement,  Cliffs  of 14 

diagrams 174 

,  Diverse 16,17,25,29,31 

,  Slopes  of 14 

',  Types  of 17 

of  the  Uinta  Mountains 176 

,  Zones  of  diverse 16, 17 

Diverse  displacement 16,17,25,29,31 

Drainage,  Antecedent  and  superimposed 12 

,  Reversed 35 

of  the  three  geological  provinces 7 

Drift 171 

Dry  Mountains,  Structure  of 206 

Dnttou,  Capt.  C.  E.,  on  Black  Butto  Quartzite 160 

Dutton,  Capt.  C.  E.,  on  reversed  drainage 35 

Ellsworth,  Mount "20 

Epochs  separating  groups 61 

Erisocrinus  typus 89 

Erosion 188 

as  a  measure  of  geological  time 33 

,  Conditions  affecting  rapidity  of 34 

Eruptive  mountains 36 

,  Types  of 18,22 

Eupachycriuus  platybasis 108 

Flaming  Gorge  district 140 

Group,  Distribution  of 151 

,  Fossils  of ,. 92 

,  relations „ 68 

,  Section  of ; 152 


INDEX.  213 

Page. 

Flaming  Gorge  Group,  typo  localities 51 

Flexure,  Maximum jg 

Flotation Ig^ 

Fossils,  Catalogue  of gy 

,  Cretaceous,  from  beyond  the  limits  of  the  Plateau  Province 101 

, Descriptions  of  new  species  of . ...  . 107 

of  the  Bitter  Creek  Group 102 

Bridger  Group 105 

Brown's  Park  Group 106 

Carboniferous  Period 38 

Cretaceous  Period 0 94 

Flaming  Gorge  Group 93 

Henry's  Fork  Group 94 

Jurassic  Period 93 

Lower  Aubrey  Group gg 

Lower  Green  Eiver  Group • 104 

Point  of  Rocks  Group 99 

Red  Wall  Group gg 

Salt  Wells  Group 97 

Sulphur  Creek  Group 95 

Tertiary  Period , 102 

Upper  Green  River  Group 104 

Upper  Aubrey  Group 91 

,  Tertiary,  from  beyond  the  limits  of  the  Plateau  Province 106 

General  observations  on  the  collections 75 

of  Carboniferous  Age 79 

Cenozoic  Age 84 

Cretaceous  Period 81 

Devonian  Age 79 

Jurassic  Period 81 

Lower  Silurian  Age 79 

Mesozoic  Age 80 

Tertiary  Period 84 

Triassic  Period 80 

Upper  Silurian  Age 79 

Geology  of  the  Uiuta  Mountains 13 J 

Gilbert,  Mr.  G.  K.,  on  age  of  Touto  Group 56 

displacements 180 

diverse  displacements 16 

Henry  Mountains 20 

structure  of  Basin  Ranges 23 

Goniobasis  Cleburni 122 

Grand  Canon  Group,  relations 70 

,  type  localities '. 61 

Schists 62 

llayden,  Dr.  F.  V 65,67 

Helix  Kauabeusis 120 

peripheria 130 

riparia 130 

Henry  Mountain  Structure 20 

Henry's  Fork  Group,  Distribution  of 153 

,  Fossils  of 94 

,  relations , 68 

,  Section  of 68, 157 

,  type  localities 50 


214  INDEX. 

Pago. 

Ho\vell,  Mr.  Edvviu  E.,  011  reversed  drainage 35 

Hydrobia  recta 132 

Utahensis 132 

Illustrations  described  ... 173 

Island  Park  district 147 

Inocerarnns  Gilbert! 113 

Howelli 114 

Junction  Mountain 10,11,145,204 

Jurassic  Period,  Fossils  of 92 

Kaibab  Structure 14,17,28,29,30 

King,  Mr.  Clarence,  on  Basin  Ranges 25 

Leidy,  Prof.J  - 72 

Leidy'sPeak 176 

Leioplax  ?  tnrricula , 133 

Lesquereux,  Prof.  Leo,  on  subdivision  of  the  Tertiary 72 

Localities  for  study  of  sedimentary  groups 44 

Lodoro  Group » 56 

,  Distribution  of 147 

,  relations 144 

,  Section  of 57 

Lower  Aubrey  Group,  Distribution  of 148 

,  Section  of - 57 

,  type  localities 3 

Lower  Green  River  Group,  Distribution  of 166 

,  Fossils  of 104 

,  relations 63,166,199 

,  type  localities 45 

Lunatia  Utahensis 122 

Marine  Tertiary  fossils 36 

Marsh,  Prof.  O.  C.,  on  geology  of  Uinta  Mountains 14 1 

separation  of  Tertiary  and  Cretaceous 72 

Marvine,  Archibald  If. VIII 

on  Park  Mountains - 27 

Meek  and  Hayden,  Messrs.,  on  subdivisions  of  the  Cretaceous 67 

Meek,  Frof.  F.  B 32,48,50 

on  section  at  Sulphur  Creek 158 

separation  of  Tertiary  and  Cretaceous 72 

Melauia  Larnnda - 131 

Mesodesma  Bishopi 128 

MonocliuaL  Ridges - 11,13,14,16 

Moraiual  deposits 171 

Mountain,  Aspen 160, 209 

,  Bruce 163 

,  Junction 10,11,145,204 

Mountains,  Appalachian 24 

composed  of  extravasated  material 18 

sedimentary  strata - 9,  21 

Dry,  Structure  of 206 

ephemeral 196 

,  Henry 20 

,Park •. 26 

,  Rocky,  defined 5 

,Tushar "     19 

,  Uiukaret .. 18,26 

3Uiuta 11,25,136,173 


INDEX.  215 

Page. 

Mountains,  Wasatch „ 30  31 

Mount  Ellsworth , 4i. 20 

Naticopsis  rcmox .  ^ 10<J 

Neritina  ?  ?  Powelli <. 110 

vol  vilineata * , ,-. , 131 

No w berry,  Dr.  J.  S.,  on  the  Plateau  Province 3 

Nomenclature  of  formations . 38 

Odontobasis  buccinoidea 124 

Ostrea  (Alectryouia)  procumbens «. 93 

sanniouis   112 

Paleontology . .  4 ?4 

Park,  Brown's,  Structure  of 4 „ t 208 

Mountains >. ..„ 26 

defined ^ , . .« ,. . 5 

Province ».»•.* . . 30 

,Orographic  structure  of 25 

Parks,  The 26 

Peaks,  Axial . 4 , 13 

,  Flanking _• t 13 

Petrology  as  related  to  disintegration . .;.  ..;_.... 182 

Phorua  exoneratus .«..*..«... 134 

Pbysa  Kauabeusis , 119 

Pilot  Butte,  Wyoming , .**.•...* 18,25 

Pisidiuiu  saginatuui »..«*.«..»... 128 

Plauorbis  (Bathyomphalus)  Kanabensis 119 

Plateau  Province ••«...•••..«..•••• ^9 

defined .t 3 

,  Dr.  J.  S.  Nswberry  on „ 3 

,  Fossils  of 74 

,  Orographic  structure  of « 25 

,  Prof.  W.  P.  Blake  on 3 

,  Sedimentary  groups  of... 37 

,  Summary  of  history  of 32 

Plateaus,  Inclined « 11 

,  Subsidiary 12 

Plateau,  Yampa,  Structure  of 202 

PlatteKiver '. 194 

Plicatula  hydrotheca 113 

Po  Canon  district 146 

Point  of  Rocks  Group,  Fossils  of 99 

,  relations 6, 155, 164 

,  Section  of 15(i,  158 

,  type  localities 47 

Province,  Basin 23,29,67 

,  Park 7,26,30 

,  Plateau 25,29 

defined 3 

Provinces,  Geological,  Characteristics  of 7 

,  defined 3,7 

,  Groups  of  sedimentary  rocks  of 8 

,  separation  indefinite 30 

,  Summary  of  history  of 32 

,  Tj  pes  of  orographic  structure  of 9 

Pupa  arenula 131 

Pupa  iucolata 130 


216  INDEX. 

Page. 

Rain-full  and  erosion 188 

Red  Creek  Group,  Distribution  of 137 

,  relations 70 

,  type  localities 62 

Wall  Group,  Distribution  of 47 

,  Sections  of 57 

,  type  localities £>•"> 

Rb.ytopb.orus  Meekii 118 

Richard's  Peak 1G3 

Ridges,  Monoclinal 11, 13, 14,  16 

,  Projecting ..-. 13,15 

River,  Colorado 193 

,  Platte 194 

,  Virgin lltt 

,  Yampa 11 

Rocky  Mountains  defined 5 

Rogers,  Messrs 9, 24 

Routes  of  travel VI 

Salt  Wells  Group,  Distribution  of 154 

,  Fossils  of 1)7 

,  relations 6G 

,  Sections  of 1 57 ,  159 

,  type  localities 49 

Sun  Francisco  Mountain 26 

Sapping 191 

Sectious,  Structure IT:'. 

Sedimentary  groups,  Distribution  of,  in  tbe  tbree  geological  provinces 

of  tbe  Plateau  Province 37 

,  Table  of 40 

Sedimentation 193 

Sbiuarump  Group,  Distribution  of 150 

,    ivlutions 68 

,  Sectious  of 53. 112 

,  type  localities 54 

Sbore-liue  of  Mesozoie  and  Tertiary  seas 

Stereograin 175 

Steward,  Mr.  John  F 57.142 

Structural  geology  of  the  I"  hit  a  Mountains 176 

Structure,  Anticlinal 10.  17. -24 

,  Appalachian 9, 24 

,  Basin  Range 16,17.  -      . 

.  Cameo * 15 

,  Henry  Mountain 

,  Kuiliab 14,17.2— 

,  Orographie,  of  the  Basin  Province 23 

Park  Province  

Plateau  Province 

,  Summary  of  orographie 

.sections 173 

Structures,  Orographie 9.  21 

Structure,  Table  Mountain 1- 

,  Tushar 19,25.26 

,  Uinkaret 1? 

,  Uinta 11. 17   -     26 

,  Volcanic  .  .  1.' 


ISTDEX- 


217 


218  INDEX. 

Page. 

Wusatch  Mountains t 31 

White  Cliff  Group,  Distribution  of 151 

,  relations 18 

,  Sections  of 53,  152 

,  type  locality 51 

White,  Dr.  C.  A.,  report  on  invertebrate  paleontology  of  the  Plateau  Province 74 

Tampa  district 14G 

Eiver , 11 

Plateau,  Structure  of 202 


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,,u  C.,?."?!<EL.EY .LIBRARIES 


C03H01111I 


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